Repeat a string: Difference between revisions
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I don't know if there is a built-in function for this, but it is easily achieved with a For loop and Concatenate Strings.<br/> |
I don't know if there is a built-in function for this, but it is easily achieved with a For loop and Concatenate Strings.<br/> |
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[[file:LabVIEW_Repeat_a_string.png]] |
[[file:LabVIEW_Repeat_a_string.png]] |
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By using built in functions |
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[[File:Panel.png|thumb]] |
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[[File:BlockDiagram.png|thumb]] |
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=={{header|Lambdatalk}}== |
=={{header|Lambdatalk}}== |
Revision as of 08:29, 17 July 2023
![Task](http://static.miraheze.org/rosettacodewiki/thumb/b/ba/Rcode-button-task-crushed.png/64px-Rcode-button-task-crushed.png)
You are encouraged to solve this task according to the task description, using any language you may know.
Take a string and repeat it some number of times.
Example: repeat("ha", 5) => "hahahahaha"
If there is a simpler/more efficient way to repeat a single “character” (i.e. creating a string filled with a certain character), you might want to show that as well (i.e. repeat-char("*", 5) => "*****").
- Metrics
- Counting
- Word frequency
- Letter frequency
- Jewels and stones
- I before E except after C
- Bioinformatics/base count
- Count occurrences of a substring
- Count how many vowels and consonants occur in a string
- Remove/replace
- XXXX redacted
- Conjugate a Latin verb
- Remove vowels from a string
- String interpolation (included)
- Strip block comments
- Strip comments from a string
- Strip a set of characters from a string
- Strip whitespace from a string -- top and tail
- Strip control codes and extended characters from a string
- Anagrams/Derangements/shuffling
- Word wheel
- ABC problem
- Sattolo cycle
- Knuth shuffle
- Ordered words
- Superpermutation minimisation
- Textonyms (using a phone text pad)
- Anagrams
- Anagrams/Deranged anagrams
- Permutations/Derangements
- Find/Search/Determine
- ABC words
- Odd words
- Word ladder
- Semordnilap
- Word search
- Wordiff (game)
- String matching
- Tea cup rim text
- Alternade words
- Changeable words
- State name puzzle
- String comparison
- Unique characters
- Unique characters in each string
- Extract file extension
- Levenshtein distance
- Palindrome detection
- Common list elements
- Longest common suffix
- Longest common prefix
- Compare a list of strings
- Longest common substring
- Find common directory path
- Words from neighbour ones
- Change e letters to i in words
- Non-continuous subsequences
- Longest common subsequence
- Longest palindromic substrings
- Longest increasing subsequence
- Words containing "the" substring
- Sum of the digits of n is substring of n
- Determine if a string is numeric
- Determine if a string is collapsible
- Determine if a string is squeezable
- Determine if a string has all unique characters
- Determine if a string has all the same characters
- Longest substrings without repeating characters
- Find words which contains all the vowels
- Find words which contain the most consonants
- Find words which contains more than 3 vowels
- Find words whose first and last three letters are equal
- Find words with alternating vowels and consonants
- Formatting
- Substring
- Rep-string
- Word wrap
- String case
- Align columns
- Literals/String
- Repeat a string
- Brace expansion
- Brace expansion using ranges
- Reverse a string
- Phrase reversals
- Comma quibbling
- Special characters
- String concatenation
- Substring/Top and tail
- Commatizing numbers
- Reverse words in a string
- Suffixation of decimal numbers
- Long literals, with continuations
- Numerical and alphabetical suffixes
- Abbreviations, easy
- Abbreviations, simple
- Abbreviations, automatic
- Song lyrics/poems/Mad Libs/phrases
- Mad Libs
- Magic 8-ball
- 99 bottles of beer
- The Name Game (a song)
- The Old lady swallowed a fly
- The Twelve Days of Christmas
- Tokenize
- Text between
- Tokenize a string
- Word break problem
- Tokenize a string with escaping
- Split a character string based on change of character
- Sequences
11l
print(‘ha’ * 5)
- Output:
hahahahaha
360 Assembly
* Repeat a string - 19/04/2020
REPEATS CSECT
USING REPEATS,R13 base register
B 72(R15) skip savearea
DC 17F'0' savearea
SAVE (14,12) save previous context
ST R13,4(R15) link backward
ST R15,8(R13) link forward
LR R13,R15 set addressability
XPRNT C24,24 print c24
LA R1,PARMLST pg=repeat(cx,ii) - repeat('abc ',6)
BAL R14,REPEAT call repeat
XPRNT PG,L'PG print pg
L R13,4(0,R13) restore previous savearea pointer
RETURN (14,12),RC=0 restore registers from calling save
REPEAT CNOP 0,4 procedure repeat(b,a,i)
STM R2,R8,REPEATSA save registers
L R2,0(R1) @b=%r1
L R3,4(R1) @a=%(r1+4)
L R4,8(R1) @i=%(r1+8)
LR R5,R3 length(a) before a
SH R5,=H'2' @lengh(a)
LH R6,0(R5) l=length(a)
LR R7,R6 l
BCTR R7,0 l-1
L R8,0(R4) i=%r4
LTR R8,R8 if i<=0
BNP RET then return
LOOP EX R7,MVCX move a to b len R6
AR R2,R6 @b+=l
BCT R8,LOOP loop i times
RET LM R2,R8,REPEATSA restore registers
BR R14 return
PARMLST DC A(PG,CX,II) parmlist
REPEATSA DS 7F local savearea
MVCX MVC 0(0,R2),0(R3) move @ R3 to @ R2
C24 DC 6C'xyz ' constant repeat - repeat('xyz ',6)
LCX DC AL2(L'CX) lengh(cc)
CX DC CL4'abc ' cx
II DC F'6' ii
PG DC CL80' ' pg
REGEQU
END REPEATS
- Output:
xyz xyz xyz xyz xyz xyz abc abc abc abc abc abc
4DOS Batch
gosub repeat ha 5
echo %@repeat[*,5]
quit
:Repeat [String Times]
do %Times%
echos %String%
enddo
echo.
return
Output shows:
hahahahaha *****
6502 Assembly
CHROUT equ $FFD2 ;KERNAL call, prints the accumulator to the screen as an ascii value.
org $0801
db $0E,$08,$0A,$00,$9E,$20,$28,$32,$30,$36,$34,$29,$00,$00,$00
lda #>TestStr
sta $11
lda #<TestStr
sta $10
ldx #5 ;number of times to repeat
loop:
jsr PrintString
dex
bne loop
RTS ;RETURN TO BASIC
PrintString:
ldy #0
loop_PrintString:
lda ($10),y ;this doesn't actually increment the pointer itself, so we don't need to back it up.
beq donePrinting
jsr CHROUT
iny
jmp loop_PrintString
donePrinting:
rts
TestStr:
db "HA",0
- Output:
READY. LOAD"*",8,1: SEARCHING FOR * LOADING READY. RUN HAHAHAHAHA READY.
68000 Assembly
Easiest way to do this is with a loop.
MOVE.W #5-1,D1
RepString:
LEA A3, MyString
MOVE.L A3,-(SP) ;PUSH A3
JSR PrintString ;unimplemented hardware-dependent printing routine, assumed to not clobber D1
MOVE.L (SP)+,A3 ;POP A3
DBRA D1,RepString
RTS ;return to basic or whatever
MyString:
DC.B "ha",0
even
8th
"ha" 5 s:*
. cr
Output shows:
hahahahaha
ABAP
This works for ABAP Version 7.40 and above
report z_repeat_string.
write repeat( val = `ha` occ = 5 ).
- Output:
hahahahaha
Action!
Proc Main()
byte REPEAT
REPEAT=5
Do
Print("ha")
REPEAT==-1
Until REPEAT=0
Do
Return
- Output:
hahahahaha
ActionScript
ActionScript does not have a built-in way to repeat a string multiple times, but the addition operator can be used to concatenate strings.
In Flex, there is the method mx.utils.StringUtil.repeat().
Iterative version
function repeatString(string:String, numTimes:uint):String
{
var output:String = "";
for(var i:uint = 0; i < numTimes; i++)
output += string;
return output;
}
Recursive version
The following double-and-add method is much faster when repeating a string many times.
function repeatRecursive(string:String, numTimes:uint):String
{
if(numTimes == 0) return "";
if(numTimes & 1) return string + repeatRecursive(string, numTimes - 1);
var tmp:String = repeatRecursive(string, numTimes/2);
return tmp + tmp;
}
Flex
import mx.utils.StringUtil;
trace(StringUtil.repeat("ha", 5));
Sample Output:
hahahahaha
Ada
In Ada multiplication of an universal integer to string gives the desired result. Here is an example of use:
with Ada.Strings.Fixed; use Ada.Strings.Fixed;
with Ada.Text_IO; use Ada.Text_IO;
procedure String_Multiplication is
begin
Put_Line (5 * "ha");
end String_Multiplication;
Sample output:
hahahahaha
Aime
call_n(5, o_text, "ha");
ALGOL 68
print (5 * "ha")
Amazing Hopper
#!/usr/bin/hopper
#include <hopper.h>
main:
{"ha"}replyby(5), println
{"ha",5}replicate, println
{0}return
hahahahaha hahahahaha
APL
Fill up a string of length 10 with 'ha':
10⍴'ha'
hahahahaha
Alternatively, define a function:
REPEAT←{(⍺×⍴⍵)⍴⍵}
5 REPEAT 'ha'
hahahahaha
AppleScript
set str to "ha"
set final_string to ""
repeat 5 times
set final_string to final_string & str
end repeat
For larger numbers of repetitions, however, it proves significantly faster to progressively double a copy of the original string (concatenating it with itself). Intermediate stages of doubling are appended to an accumulator wherever required for binary composition of the target number.
See the technique of 'Egyptian Multiplication' described in the Rhind Mathematical Papyrus at the British Museum.
replicate(5000, "ha")
-- Repetition by 'Egyptian multiplication' -
-- progressively doubling a list, appending
-- stages of doubling to an accumulator where needed for
-- binary assembly of a target length.
-- replicate :: Int -> String -> String
on replicate(n, s)
set out to ""
if n < 1 then return out
set dbl to s
repeat while (n > 1)
if (n mod 2) > 0 then set out to out & dbl
set n to (n div 2)
set dbl to (dbl & dbl)
end repeat
return out & dbl
end replicate
Applesoft BASIC
FOR I = 1 TO 5 : S$ = S$ + "HA" : NEXT
? "X" SPC(20) "X"
Output:
X X
Arturo
print repeat "ha" 5
- Output:
hahahahaha
AutoHotkey
MsgBox % Repeat("ha",5)
Repeat(String,Times)
{
Loop, %Times%
Output .= String
Return Output
}
AutoIt
#include <String.au3>
ConsoleWrite(_StringRepeat("ha", 5) & @CRLF)
AWK
function repeat( str, n, rep, i )
{
for( ; i<n; i++ )
rep = rep str
return rep
}
BEGIN {
print repeat( "ha", 5 )
}
Babel
main: { "ha" 5 print_repeat }
print_repeat!: { <- { dup << } -> times }
Outputs:
hahahahaha
The '<<' operator prints, 'dup' duplicates the top-of-stack, 'times' does something x number of times. The arrows mean down (<-) and up (->) respectively - it would require a lengthy description to explain what this means, refer to the doc/babel_ref.txt file in the github repo linked from Babel
BaCon
To repeat a string:
DOTIMES 5
s$ = s$ & "ha"
DONE
PRINT s$
- Output:
hahahahaha
To repeat one single character:
PRINT FILL$(5, ASC("x"))
- Output:
xxxxx
BASIC
BASIC256
function StringRepeat$ (s$, n)
cad$ = ""
for i = 1 to n
cad$ += s$
next i
return cad$
end function
print StringRepeat$("rosetta", 1)
print StringRepeat$("ha", 5)
print StringRepeat$("*", 5)
end
QBasic
FUNCTION StringRepeat$ (s$, n)
cad$ = ""
FOR i = 1 TO n
cad$ = cad$ + s$
NEXT i
StringRepeat$ = cad$
END FUNCTION
PRINT StringRepeat$("rosetta", 1)
PRINT StringRepeat$("ha", 5)
PRINT StringRepeat$("*", 5)
END
True BASIC
FUNCTION StringRepeat$ (s$, n)
LET cad$ = ""
FOR i = 1 TO n
LET cad$ = cad$ & s$
NEXT i
LET StringRepeat$ = cad$
END FUNCTION
PRINT StringRepeat$("rosetta", 1)
PRINT StringRepeat$("ha", 5)
PRINT StringRepeat$("*", 5)
END
Yabasic
sub StringRepeat$ (s$, n)
cad$ = ""
for i = 1 to n
cad$ = cad$ + s$
next i
return cad$
end sub
print StringRepeat$("rosetta", 1)
print StringRepeat$("ha", 5)
print StringRepeat$("*", 5)
end
Batch File
Commandline implementation
@echo off
if "%2" equ "" goto fail
setlocal enabledelayedexpansion
set char=%1
set num=%2
for /l %%i in (1,1,%num%) do set res=!res!%char%
echo %res%
:fail
'Function' version
@echo off
set /p a=Enter string to repeat :
set /p b=Enter how many times to repeat :
set "c=1"
set "d=%b%"
:a
echo %a%
set "c=%c%+=1"
if /i _"%c%"==_"%d%" (exit /b)
goto :a
'Function' version 2
@echo off
@FOR /L %%i in (0,1,9) DO @CALL :REPEAT %%i
@echo That's it!
@FOR /L %%i in (0,1,9) DO @CALL :REPEAT %%i
@echo.
@echo And that!
@GOTO END
:REPEAT
@echo|set /p="*"
@GOTO:EOF
:END
BBC BASIC
PRINT STRING$(5, "ha")
beeswax
p <
p0~1<}~< d@<
_VT@1~>yg~9PKd@M'd;
Example:
julia> beeswax("repeat a string.bswx") sha i5 hahahahaha Program finished!
s
tells the user that the program expects a string as input.
i
tells the user that the program expects an integer as input.
Beef
String s = new String('X', 5);
s.Replace("X", "ha");
And for single character repeats
String s1 = scope .();
s1.PadLeft(5, '*');
Befunge
v> ">:#,_v
>29*+00p>~:"0"- #v_v $
v ^p0p00:-1g00< $ >
v p00&p0-1g00+4*65< >00g1-:00p#^_@
Input sample:
ha05
Input string has to be zero terminated and less than 18 characters.
Output sample:
hahahahaha
BQN
⥊
(reshape) can all by itself be used to repeat a string to a particular length. This function is just a wrapper around it to repeat n times.
Repeat ← ×⟜≠ ⥊ ⊢
•Show 5 Repeat "Hello"
"HelloHelloHelloHelloHello"
Bracmat
The code almost explains itself. The repetions are accumulated in a list rep
. The str
concatenates all elements into a single string, ignoring the white spaces separating the elements.
(repeat=
string N rep
. !arg:(?string.?N)
& !string:?rep
& whl
' (!N+-1:>0:?N&!string !rep:?rep)
& str$!rep
);
repeat$(ha.5) hahahahaha
Brainf***
Prints "ha" 10 times. Note that this method only works for a number of repetitions that fit into the cell size.
+++++ +++++ init first as 10 counter
[-> +++++ +++++<] we add 10 to second each loopround
Now we want to loop 5 times to follow std
+++++
[-> ++++ . ----- -- . +++<] print h and a each loop
and a newline because I'm kind and it looks good
+++++ +++++ +++ . --- .
Brat
p "ha" * 5 #Prints "hahahahaha"
Burlesque
blsq ) 'h5?*
"hhhhh"
blsq ) "ha"5.*\[
"hahahahaha"
C
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
char * string_repeat( int n, const char * s ) {
size_t slen = strlen(s);
char * dest = malloc(n*slen+1);
int i; char * p;
for ( i=0, p = dest; i < n; ++i, p += slen ) {
memcpy(p, s, slen);
}
*p = '\0';
return dest;
}
int main() {
char * result = string_repeat(5, "ha");
puts(result);
free(result);
return 0;
}
A variation.
...
char *string_repeat(const char *str, int n)
{
char *pa, *pb;
size_t slen = strlen(str);
char *dest = malloc(n*slen+1);
pa = dest + (n-1)*slen;
strcpy(pa, str);
pb = --pa + slen;
while (pa>=dest) *pa-- = *pb--;
return dest;
}
To repeat a single character
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
char * char_repeat( int n, char c ) {
char * dest = malloc(n+1);
memset(dest, c, n);
dest[n] = '\0';
return dest;
}
int main() {
char * result = char_repeat(5, '*');
puts(result);
free(result);
return 0;
}
If you use GLib, simply use g_strnfill ( gsize length, gchar fill_char )
function.
C#
string s = "".PadLeft(5, 'X').Replace("X", "ha");
or (with .NET 2+)
string s = new String('X', 5).Replace("X", "ha");
or (with .NET 2+)
string s = String.Join("ha", new string[5 + 1]);
or (with .NET 4+)
string s = String.Concat(Enumerable.Repeat("ha", 5));
To repeat a single character:
string s = "".PadLeft(5, '*');
or (with .NET 2+)
string s = new String('*', 5);
C++
#include <string>
#include <iostream>
std::string repeat( const std::string &word, int times ) {
std::string result ;
result.reserve(times*word.length()); // avoid repeated reallocation
for ( int a = 0 ; a < times ; a++ )
result += word ;
return result ;
}
int main( ) {
std::cout << repeat( "Ha" , 5 ) << std::endl ;
return 0 ;
}
To repeat a single character:
#include <string>
#include <iostream>
int main( ) {
std::cout << std::string( 5, '*' ) << std::endl ;
return 0 ;
}
recursive version
#include <string>
#include <iostream>
std::string repeat( const std::string &word, uint times ) {
return
times == 0 ? "" :
times == 1 ? word :
times == 2 ? word + word :
repeat(repeat(word, times / 2), 2) +
repeat(word, times % 2);
}
int main( ) {
std::cout << repeat( "Ha" , 5 ) << std::endl ;
return 0 ;
}
Ceylon
shared void repeatAString() {
print("ha".repeat(5));
}
Clipper
Also works with Harbour Project compiler Harbour 3.0.0 (Rev. 16951)
Replicate( "Ha", 5 )
Clojure
(apply str (repeat 5 "ha"))
COBOL
Virtually a one-liner.
IDENTIFICATION DIVISION.
PROGRAM-ID. REPEAT-PROGRAM.
DATA DIVISION.
WORKING-STORAGE SECTION.
77 HAHA PIC A(10).
PROCEDURE DIVISION.
MOVE ALL 'ha' TO HAHA.
DISPLAY HAHA.
STOP RUN.
- Output:
hahahahaha
ColdFusion
<cfset word = 'ha'>
<Cfset n = 5>
<Cfoutput>
<Cfloop from="1" to="#n#" index="i">#word#</Cfloop>
</Cfoutput>
Common Lisp
(defun repeat-string (n string)
(with-output-to-string (stream)
(loop repeat n do (write-string string stream))))
A version which allocates the result string in one step:
(defun repeat-string (n string
&aux
(len (length string))
(result (make-string (* n len)
:element-type (array-element-type string))))
(loop repeat n
for i from 0 by len
do (setf (subseq result i (+ i len)) string))
result)
For those who love one-liners, even at the expense of readability:
(defun repeat-string (n string)
(format nil "~V@{~a~:*~}" n string))
(princ (repeat-string 5 "hi"))
A single character may be repeated using just the builtin make-string
:
(make-string 5 :initial-element #\X)
produces “XXXXX”.
Crystal
puts "ha" * 5
hahahahaha
D
Repeating a string:
import std.stdio, std.array;
void main() {
writeln("ha".replicate(5));
}
Repeating a character with vector operations:
import std.stdio;
void main() {
char[] chars; // create the dynamic array
chars.length = 5; // set the length
chars[] = '*'; // set all characters in the string to '*'
writeln(chars);
}
DCL
Not exactly what the task asks for but at least it is something;
$ write sys$output f$fao( "!AS!-!AS!-!AS!-!AS!-!AS", "ha" )
$ write sys$output f$fao( "!12*d" )
- Output:
$ @repeat_a_string_and_then_character hahahahaha dddddddddddd
Delphi
Repeat a string
function RepeatString(const s: string; count: cardinal): string;
var
i: Integer;
begin
for i := 1 to count do
Result := Result + s;
end;
Writeln(RepeatString('ha',5));
Repeat a character
Writeln( StringOfChar('a',5) );
Using recursion
function RepeatStr(const s: string; i: Cardinal): string;
begin
if i = 0 then
result := ''
else
result := s + RepeatStr(s, i-1)
end;
Built in RTL function:
StrUtils.DupeString
DWScript
Repeat a string
PrintLn( StringOfString('abc',5) );
Repeat a character
PrintLn( StringOfChar('a',5) );
Dyalect
String.Repeat("ha", 5)
Déjà Vu
!. concat( rep 5 "ha" )
- Output:
"hahahahaha"
E
"ha" * 5
ECL
After version 4.2.2
IMPORT STD; //Imports the Standard Library
STRING MyBaseString := 'abc';
RepeatedString := STD.Str.Repeat(MyBaseString,3);
RepeatedString; //returns 'abcabcabc'
Before version 4.2.2
RepeatString(STRING InStr, INTEGER Cnt) := FUNCTION
rec := {STRING Str};
ds := DATASET(Cnt,TRANSFORM(rec,SELF.Str := InStr));
res := ITERATE(ds,TRANSFORM(rec,SELF.Str := LEFT.Str + RIGHT.Str));
RETURN Res[Cnt].Str;
END;
RepeatString('ha',3);
RepeatString('Who',2);
Ecstasy
String funny = "ha" * 5;
String stars = '*' * 80;
Egison
(S.concat (take 5 (repeat1 "ha")))
Eiffel
repeat_string(a_string: STRING; times: INTEGER): STRING
require
times_positive: times > 0
do
Result := a_string.multiply(times)
end
Elena
ELENA 4.x :
import system'routines;
import extensions;
import extensions'text;
public program()
{
var s := new Range(0, 5).selectBy:(x => "ha").summarize(new StringWriter())
}
Elixir
String.duplicate("ha", 5)
Emacs Lisp
Going via a list to repeat the desired string:
(apply 'concat (make-list 5 "ha"))
A single character can be repeated with make-string
:
(make-string 5 ?x)
The cl-loop
macro can repeat and concatenate:
(require 'cl-lib)
(cl-loop repeat 5 concat "ha")
Erlang
repeat(X,N) ->
lists:flatten(lists:duplicate(N,X)).
This will duplicate a string or character N times to produce a new string.
ERRE
PROCEDURE REPEAT_STRING(S$,N%->REP$)
LOCAL I%
REP$=""
FOR I%=1 TO N% DO
REP$=REP$+S$
END FOR
END PROCEDURE
Note: If N% is less than 1, the result is the empty string "".If S$ is a one-character string
you can use the predefined function STRING$
as REP$=STRING$(S$,N%)
.
Euphoria
A simple loop will do:
sequence s = ""
for i = 1 to 5 do s &= "ha" end for
puts(1,s)
hahahahaha
For repeating a single character:
sequence s = repeat('*',5)
*****
For repeating a string or sequence of numbers:
include std/console.e -- for display
include std/sequence.e -- for repeat_pattern
sequence s = repeat_pattern("ha",5)
sequence n = repeat_pattern({1,2,3},5)
display(s)
display(n)
hahahahaha
{1,2,3,1,2,3,1,2,3,1,2,3,1,2,3}
But wait, here's another way:
include std/console.e -- for display
include std/sequence.e -- for flatten
sequence s = flatten(repeat("ha",5))
display(s)
note: repeat creates a sequence of ha's as shown below; flatten concatenates them.
{
"ha",
"ha",
"ha",
"ha",
"ha"
}
Explore
The Scratch solution, which requires making variables named "String", "Count", and "Repeated" first, works, unmodified:
https://i.ibb.co/yX3ybt7/Repeat-a-string-in-Explore-using-the-Scratch-solution.png
This example uses a special block located in the Strings category, and also outputs the results of the repeating of the string to a "say" block:
https://i.ibb.co/71x9rwn/Repeat-a-string-in-Explore-using-a-special-block.png
F#
> String.replicate 5 "ha";;
val it : string = "hahahahaha"
Or
> String.Concat( Array.create 5 "ha" );;
val it : string = "hahahahaha"
Factor
: repeat-string ( str n -- str' ) swap <repetition> concat ;
"ha" 5 repeat-string print
Forth
: place-n { src len dest n -- }
0 dest c!
n 0 ?do src len dest +place loop ;
s" ha" pad 5 place-n
pad count type \ hahahahaha
The same code without the use of locals:
: place-n ( src len dest n -- )
swap >r 0 r@ c!
begin dup while -rot 2dup r@ +place rot 1- repeat
r> 2drop 2drop ;
s" ha" pad 5 place-n
pad count type \ hahahahaha
Filling a string with a single character is supported by ANS-Forth:
pad 10 char * fill \ repeat a single character
pad 10 type \ **********
Fortran
program test_repeat
write (*, '(a)') repeat ('ha', 5)
end program test_repeat
Output:
hahahahaha
Free Pascal
strUtils.dupeString('ha', 5)
Repetition of a single character:
stringOfChar('*', 5)
If the repeated character happens to be the space character:
space(5)
FreeBASIC
' FB 1.05.0 Win64
' A character is essentially a string of length 1 in FB though there is a built-in function, String,
' which creates a string by repeating a character a given number of times.
' To avoid repeated concatenation (a slow operation) when the string to be repeated has a length
' greater than one, we instead create a buffer of the required size and then fill that.
Function repeat(s As String, n As Integer) As String
If n < 1 Then Return ""
If n = 1 Then Return s
Var size = Len(s)
If size = 0 Then Return s ' empty string
If size = 1 Then Return String(n, s[0]) ' repeated single character
Var buffer = Space(size * n) 'create buffer for size > 1
For i As Integer = 0 To n - 1
For j As Integer = 0 To size - 1
buffer[i * size + j] = s[j]
Next j
Next i
Return buffer
End Function
Print repeat("rosetta", 1)
Print repeat("ha", 5)
Print repeat("*", 5)
Print
Print "Press any key to quit program"
Sleep
- Output:
rosetta hahahahaha *****
Frink
println[repeat["ha", 5]]
FutureBasic
include "NSLog.incl"
CFStringRef repeatStr
repeatStr = @"Hello, World!\n"
NSLog( @"%@", fn StringByPaddingToLength( @"", 50 * len(repeatStr), repeatStr, 0 ) )
HandleEvents
- Output:
[50 line repetitions of "Hello, World!"]
Gambas
Click this link to run this code
Public Sub Main()
Print String$(5, "ha")
End
Output = hahahahaha
GAP
Concatenation(ListWithIdenticalEntries(10, "BOB "));
"BOB BOB BOB BOB BOB BOB BOB BOB BOB BOB "
Glee
'*' %% 5
'ha' => Str;
Str# => Len;
1..Len %% (Len * 5) => Idx;
Str [Idx] $;
'ha'=>S[1..(S#)%%(S# *5)]
Go
fmt.Println(strings.Repeat("ha", 5)) // ==> "hahahahaha"
There is no special way to repeat a single character, other than to convert the character to a string. The following works:
fmt.Println(strings.Repeat(string('h'), 5)) // prints hhhhh
Groovy
println 'ha' * 5
Harbour
? Replicate( "Ha", 5 )
Haskell
For a string of finite length:
concat $ replicate 5 "ha"
Or with list-monad (a bit obscure):
[1..5] >> "ha"
Or with Control.Applicative:
[1..5] *> "ha"
For an infinitely long string:
cycle "ha"
To repeat a single character:
replicate 5 '*'
Or, unpacking the mechanism of replicate a little, and using a mappend-based rep in lieu of the cons-based repeat, so that we can skip a subsequent concat:
repString :: String -> Int -> String
repString s n =
let rep x = xs
where
xs = mappend x xs
in take (n * length s) (rep s)
main :: IO ()
main = print $ repString "ha" 5
- Output:
"hahahahaha"
As the number of repetitions grows, however, it may become more efficient to repeat by progressive duplication (mappend to self), mappending to an accumulator only where required for binary composition of the target length. (i.e. Rhind Papyrus 'Egyptian' or 'Ethiopian' multiplication):
import Data.Tuple (swap)
import Data.List (unfoldr)
import Control.Monad (join)
-- BY RHIND PAPYRUS 'EGYPTIAN' OR 'ETHIOPIAN' MULTIPLICATION ------------------
repString :: Int -> String -> String
repString n s =
foldr
(\(d, x) a ->
if d > 0 -- Is this power of 2 needed for the binary recomposition ?
then mappend a x
else a)
mempty $
zip
(unfoldr
(\h ->
if h > 0
then Just $ swap (quotRem h 2) -- Binary decomposition of n
else Nothing)
n)
(iterate (join mappend) s) -- Iterative duplication ( mappend to self )
-- TEST -----------------------------------------------------------------------
main :: IO ()
main = print $ repString 500 "ha"
HicEst
CHARACTER out*20
EDIT(Text=out, Insert="ha", DO=5)
Icon and Unicon
The procedure repl is a supplied function in Icon and Unicon.
If it weren't, one way to write it is:
Idris
strRepeat : Nat -> String -> String
strRepeat Z s = ""
strRepeat (S n) s = s ++ strRepeat n s
chrRepeat : Nat -> Char -> String
chrRepeat Z c = ""
chrRepeat (S n) c = strCons c $ chrRepeat n c
Inform 7
Home is a room.
To decide which indexed text is (T - indexed text) repeated (N - number) times:
let temp be indexed text;
repeat with M running from 1 to N:
let temp be "[temp][T]";
decide on temp.
When play begins:
say "ha" repeated 5 times;
end the story.
IS-BASIC
10 PRINT STRING$("ha",5)
100 DEF STRING$(S$,N)
105 LET ST$=""
110 FOR I=1 TO N
120 LET ST$=ST$&S$
130 NEXT
140 LET STRING$=ST$
150 END DEF
J
5 # '*' NB. repeat each item 5 times
*****
5 # 'ha' NB. repeat each item 5 times
hhhhhaaaaa
5 ((* #) $ ]) 'ha' NB. repeat array 5 times
hahahahaha
5 ;@# < 'ha' NB. using boxing to treat the array as a whole
hahahahaha
Java
There are a few ways to achieve this in Java.
Starting with Java 11 you can use the String.repeat method.
"ha".repeat(5);
Which, if you view its implementation, is just using the Arrays.fill method.
String[] strings = new String[5];
Arrays.fill(strings, "ha");
StringBuilder repeated = new StringBuilder();
for (String string : strings)
repeated.append(string);
And if you look at the 'Arrays.fill' implementation, it's just a for-loop, which is likely the most idiomatic approach.
String string = "ha";
StringBuilder repeated = new StringBuilder();
int count = 5;
while (count-- > 0)
repeated.append(string);
Or
Before Java 11 there was no method or operator to do this in Java, so you had to do it yourself.
public static String repeat(String str, int times) {
StringBuilder sb = new StringBuilder(str.length() * times);
for (int i = 0; i < times; i++)
sb.append(str);
return sb.toString();
}
public static void main(String[] args) {
System.out.println(repeat("ha", 5));
}
Or even shorter:
public static String repeat(String str, int times) {
return new String(new char[times]).replace("\0", str);
}
In Apache Commons Lang, there is a StringUtils.repeat() method.
JavaScript
Extending the String prototype
This solution creates an empty array of length n+1, then uses the array's join method to effectively concatenate the string n times. Note that extending the prototype of built-in objects is not a good idea if the code is to run in a shared workspace.
String.prototype.repeat = function(n) {
return new Array(1 + (n || 0)).join(this);
}
console.log("ha".repeat(5)); // hahahahaha
As of ES6, `repeat` is built in, so this can be written as:
console.log("ha".repeat(5)); // hahahahaha
Repetition by Egyptian multiplication
For larger numbers of repetitions, however, it proves significantly faster to progressively double a copy of the original string (concatenating it with itself). Intermediate stages of doubling are appended to an accumulator wherever required for binary composition of the target number.
See the technique of 'Egyptian Multiplication' described in the Rhind Mathematical Papyrus at the British Museum.
(() => {
'use strict';
// replicate :: Int -> String -> String
const replicate = (n, s) => {
let v = [s],
o = [];
if (n < 1) return o;
while (n > 1) {
if (n & 1) o = o + v;
n >>= 1;
v = v + v;
}
return o.concat(v);
};
return replicate(5000, "ha")
})();
Concat . replicate
Or, more generically, we could derive repeat as the composition of concat and replicate
(() => {
'use strict';
// repeat :: Int -> String -> String
const repeat = (n, s) =>
concat(replicate(n, s));
// GENERIC FUNCTIONS ------------------------------------------------------
// concat :: [[a]] -> [a] | [String] -> String
const concat = xs =>
xs.length > 0 ? (() => {
const unit = typeof xs[0] === 'string' ? '' : [];
return unit.concat.apply(unit, xs);
})() : [];
// replicate :: Int -> a -> [a]
const replicate = (n, x) =>
Array.from({
length: n
}, () => x);
// TEST -------------------------------------------------------------------
return repeat(5, 'ha');
})();
- Output:
hahahahaha
Joy
DEFINE repeat == "" rotate [concat] cons times.
"ha" 5 repeat.
jq
"a " * 3 # => "a a a "
Note that if the integer multiplicand is 0, then the result is the JSON value null.
Julia
@show "ha" ^ 5
# The ^ operator is really just call to the `repeat` function
@show repeat("ha", 5)
K
,/5#,"ha"
"hahahahaha"
5#"*"
"*****"
Kotlin
fun main(args: Array<String>) {
println("ha".repeat(5))
}
Or more fancy:
operator fun String.times(n: Int) = this.repeat(n)
fun main(args: Array<String>) = println("ha" * 5)
LabVIEW
I don't know if there is a built-in function for this, but it is easily achieved with a For loop and Concatenate Strings.
By using built in functions
![](http://static.miraheze.org/rosettacodewiki/thumb/e/e2/Panel.png/300px-Panel.png)
![](http://static.miraheze.org/rosettacodewiki/thumb/4/44/BlockDiagram.png/300px-BlockDiagram.png)
Lambdatalk
{S.map {lambda {_} ha} {S.serie 1 10}}
-> ha ha ha ha ha ha ha ha ha ha
or
{S.replace \s
by
in {S.map {lambda {_} ha}
{S.serie 1 10}}}
-> hahahahahahahahahaha
or
{def repeat
{lambda {:w :n}
{if {< :n 0}
then
else :w{repeat :w {- :n 1}}}}}
-> repeat
{repeat ha 10}
-> hahahahahahahahahahaha
Lang
# Repeat text function
fn.println(fn.repeatText(5, ha))
# Output: hahahahaha
# Mul operator
fn.println(parser.op(ha * 5))
# Output: hahahahaha
# Mul operator function
fn.println(fn.mul(ha, 5))
# Output: hahahahaha
langur
This example looks like Perl, but the x operator doesn't just multiply strings in langur.
"ha" x 5
Lasso
'ha'*5 // hahahahaha
loop(5) => {^ 'ha' ^} // hahahahaha
LFE
(string:copies '"ha" 5)
Liberty BASIC
a$ ="ha "
print StringRepeat$( a$, 5)
end
function StringRepeat$( in$, n)
o$ =""
for i =1 to n
o$ =o$ +in$
next i
StringRepeat$ =o$
end function
Lingo
- Take a string and repeat it some number of times.
on rep (str, n)
res = ""
repeat with i = 1 to n
put str after res
end repeat
return res
end
put rep("ha", 5)
-- "hahahahaha"
- If there is a simpler/more efficient way to repeat a single “character”...
put bytearray(5, chartonum("*")).readRawString(5)
-- "*****"
LiveCode
on mouseUp
put repeatString("ha", 5)
end mouseUp
function repeatString str n
repeat n times
put str after t
end repeat
return t
end repeatString
Logo
to copies :n :thing [:acc "||]
if :n = 0 [output :acc]
output (copies :n-1 :thing combine :acc :thing)
end
or using cascade:
show cascade 5 [combine "ha ?] "|| ; hahahahaha
Lhogho doesn't have cascade (yet), nor does it have the initialise a missing parameter capability demonstrated by the [:acc "||] above.
to copies :n :thing :acc
if :n = 0 [output :acc]
output (copies :n-1 :thing combine :acc :thing)
end
print copies 5 "ha "||
Lua
function repeats(s, n) return n > 0 and s .. repeats(s, n-1) or "" end
Or use native string library function
string.rep(s,n)
Maple
There are many ways to do this in Maple. First, the "right" (most efficient) way is to use the supplied procedures for this purpose.
> use StringTools in
> Repeat( "abc", 10 ); # repeat an arbitrary string
> Fill( "x", 20 ) # repeat a character
> end use;
"abcabcabcabcabcabcabcabcabcabc"
"xxxxxxxxxxxxxxxxxxxx"
These next two are essentially the same, but are less efficient (though still linear) because they create a sequence of 10 strings before concatenating them (with the built-in procedure cat) to form the result.
> cat( "abc" $ 10 );
"abcabcabcabcabcabcabcabcabcabc"
> cat( seq( "abc", i = 1 .. 10 ) );
"abcabcabcabcabcabcabcabcabcabc"
You can build up a string in a loop, but this is highly inefficient (quadratic); don't do this.
> s := "":
> to 10 do s := cat( s, "abc" ) end: s;
"abcabcabcabcabcabcabcabcabcabc"
If you need to build up a string incrementally, use a StringBuffer object, which keeps things linear.
Finally, note that strings and characters are not distinct datatypes in Maple; a character is just a string of length one.
Mathematica /Wolfram Language
StringRepeat["ha", 5]
MATLAB / Octave
function S = repeat(s , n)
S = repmat(s , [1,n]) ;
return
Note 1: The repetition is returned, not displayed.
Note 2: To repeat a string, use single quotes. Example: S=repeat('ha',5)
Maxima
"$*"(s, n) := apply(sconcat, makelist(s, n))$
infix("$*")$
"abc" $* 5;
/* "abcabcabcabcabc" */
Mercury
Mercury's 'string' module provides an efficient char-repeater. The following uses string.builder to repeat strings.
:- module repeat.
:- interface.
:- import_module string, char, int.
:- func repeat_char(char, int) = string.
:- func repeat(string, int) = string.
:- implementation.
:- import_module stream, stream.string_writer, string.builder.
repeat_char(C, N) = string.duplicate_char(C, N).
repeat(String, Count) = Repeated :-
S0 = string.builder.init,
Repeated = string.builder.to_string(S),
printn(string.builder.handle, Count, String, S0, S).
:- pred printn(Stream, int, string, State, State)
<= (stream.writer(Stream, string, State),
stream.writer(Stream, character, State)).
:- mode printn(in, in, in, di, uo) is det.
printn(Stream, N, String, !S) :-
( N > 0 ->
print(Stream, String, !S),
printn(Stream, N - 1, String, !S)
; true ).
min
"ha" 5 repeat print
- Output:
hahahahaha
MiniScript
str = "Lol"
print str * 5
- Output:
LolLolLolLolLol
Mirah
x = StringBuilder.new
5.times do
x.append "ha"
end
puts x # ==> "hahahahaha"
Monte
var s := "ha " * 5
traceln(s)
MontiLang
|ha| 5 * PRINT .
Or with a loop
FOR 5
|ha| OUT .
ENDFOR || PRINT .
Or ...
|ha| FOR 5 OUT ENDFOR . || PRINT .
MUMPS
RPTSTR(S,N)
;Repeat a string S for N times
NEW I
FOR I=1:1:N WRITE S
KILL I
QUIT
RPTSTR1(S,N) ;Functionally equivalent, but denser to read
F I=1:1:N W S
Q
This last example uses the $PIECE function.
;Even better (more terse)
S x="",$P(x,"-",10)="-"
W x
Nanoquery
In Nanoquery, multiplying strings by an integer returns a new string with the original value repeated.
"ha" * 5
Neko
/* Repeat a string, in Neko */
var srep = function(s, n) {
var str = ""
while n > 0 {
str += s
n -= 1
}
return str
}
$print(srep("ha", 5), "\n")
- Output:
prompt$ nekoc srep.neko prompt$ neko srep hahahahaha
Nemerle
Any of the methods shown in the C# solution would also work for Nemerle, but they're all semantically awkward. This example uses an extension method to wrap one of the awkward techniques in order to clarify the semantics (which is also possible in C#, there's nothing really Nemerle specific here except the syntax).
using System;
using System.Console;
module StrRep
{
Repeat(this s : string, n : int) : string
{
String('x', n).Replace("x", s)
}
Main() : void
{
WriteLine("ha".Repeat(5));
WriteLine("*".Repeat(5));
WriteLine(String('*', 5)); // repeating single char
}
}
NetRexx
NetRexx has built in functions to manipulate strings. The most appropriate for this task is the copies()
function:
/* NetRexx */
ha5 = 'ha'.copies(5)
There are several other built-in functions that can be used to achieve the same result depending on need:
/* NetRexx */
sampleStr = 'ha' -- string to duplicate
say ' COPIES:' sampleStr.copies(5)
say 'CHANGESTR:' '.....'.changestr('.', sampleStr)
sampleChr = '*' -- character to duplicate
say ' LEFT:' sampleChr.left(5, sampleChr)
say ' RIGHT:' sampleChr.right(5, sampleChr)
say ' CENTRE:' sampleChr.centre(5, sampleChr)
say ' OVERLAY:' sampleChr.overlay(sampleChr, 1, 5, sampleChr)
say ' SUBSTR:' ''.substr(1, 5, sampleChr)
say 'TRANSLATE:' '.....'.translate(sampleChr, '.')
NewLISP
(dup "ha" 5)
Nim
import strutils
# Repeat a char.
echo repeat('a', 5) # -> "aaaaa".
# Repeat a string.
echo repeat("ha", 5) # -> "hahahahaha".
Objeck
bundle Default {
class Repeat {
function : Main(args : String[]) ~ Nil {
Repeat("ha", 5)->PrintLine();
}
function : Repeat(string : String, max : Int) ~ String {
repeat : String := String->New();
for(i := 0; i < max; i += 1;) {
repeat->Append(string);
};
return repeat;
}
}
}
Objective-C
Objective-C allows developers to extend existing an existing class by adding additional methods to the class without needing to subclass. These extensions are called categories. Category methods are available to all instances of the class, as well as any instances of its subclasses.
This task provides us with an opportunity to visit this aspect of the language feature.
We will extend NSString, the de facto Objective-C string class in environments that are either compatible with or descend directly from the OPENSTEP specification, such as GNUstep and Mac OS X, respectively, with a method that accomplishes the described task.
@interface NSString (RosettaCodeAddition)
- (NSString *) repeatStringByNumberOfTimes: (NSUInteger) times;
@end
@implementation NSString (RosettaCodeAddition)
- (NSString *) repeatStringByNumberOfTimes: (NSUInteger) times {
return [@"" stringByPaddingToLength:[self length]*times withString:self startingAtIndex:0];
}
@end
Now, let's put it to use:
// Instantiate an NSString by sending an NSString literal our new
// -repeatByNumberOfTimes: selector.
NSString *aString = [@"ha" repeatStringByNumberOfTimes:5];
// Display the NSString.
NSLog(@"%@", aString);
OCaml
Since Ocaml 4.02 strings are immutable, as is convenient for a functional language. Mutable strings are now implemented in the module Bytes.
let string_repeat s n =
let s = Bytes.of_string s in
let len = Bytes.length s in
let res = Bytes.create (n * len) in
for i = 0 to pred n do
Bytes.blit s 0 res (i * len) len
done;
(Bytes.to_string res)
;;
which gives the signature
val string_repeat : string -> int -> string = <fun>
testing in the toplevel:
# string_repeat "Hiuoa" 3 ;;
- : string = "HiuoaHiuoaHiuoa"
Alternately create an array initialized to s, and concat:
let string_repeat s n =
String.concat "" (Array.to_list (Array.make n s))
;;
Or:
let string_repeat s n =
Array.fold_left (^) "" (Array.make n s)
;;
To repeat a single character use:
String.make 5 '*'
Oforth
StringBuffer new "abcd" <<n(5)
OpenEdge/Progress
MESSAGE FILL( "ha", 5 ) VIEW-AS ALERT-BOX.
OxygenBasic
'REPEATING A CHARACTER
print string 10,"A" 'result AAAAAAAAAA
'REPEATING A STRING
function RepeatString(string s,sys n) as string
sys i, le=len s
if le=0 then exit function
n*=le
function=nuls n
'
for i=1 to n step le
mid function,i,s
next
end function
print RepeatString "ABC",3 'result ABCABCABC
Oz
We have to write a function for this:
declare
fun {Repeat Xs N}
if N > 0 then
{Append Xs {Repeat Xs N-1}}
else
nil
end
end
in
{System.showInfo {Repeat "Ha" 5}}
PARI/GP
Version #1. Based on recursion.
This solution is recursive and unimaginably bad. Slightly less bad versions can be designed, but that's not the point: don't use GP for text processing if you can avoid it. If you really need to, it's easy to create an efficient function in PARI (see C) and pass that to GP.
repeat(s,n)={
if(n, Str(repeat(s, n-1), s), "")
};
concat()
joins together a vector of strings, in this case a single string repeated.
repeat(s,n)=concat(vector(n,i, s));
This solution is recursive and slightly less bad than the others for large n.
repeat(s,n)={
if(n<4, return(concat(vector(n,i, s))));
if(n%2,
Str(repeat(Str(s,s),n\2),s)
,
repeat(Str(s,s),n\2)
);
}
Version #2. Simple loop based.
Basic set of string functions is very handy for presentation purposes. At the same time, it is true that PARI/GP is not an appropriate tool for the heavy text processing.
\\ Repeat a string str the specified number of times ntimes and return composed string.
\\ 3/3/2016 aev
srepeat(str,ntimes)={
my(srez=str,nt=ntimes-1);
if(ntimes<1||#str==0,return(""));
if(ntimes==1,return(str));
for(i=1,nt, srez=concat(srez,str));
return(srez);
}
{
\\ TESTS
print(" *** Testing srepeat:");
print("1.",srepeat("a",5));
print("2.",srepeat("ab",5));
print("3.",srepeat("c",1));
print("4.|",srepeat("d",0),"|");
print("5.|",srepeat("",5),"|");
print1("6."); for(i=1,10000000, srepeat("e",10));
}
- Output:
*** Testing srepeat: 1.aaaaa 2.ababababab 3.c 4.|| 5.|| 6. (16:00) gp > ## *** last result computed in 1min, 2,939 ms.
Pascal
See Delphi or Free Pascal, as standard Pascal does not know strings of unlimited length.
Perl
"ha" x 5
Phix
?repeat('*',5) ?join(repeat("ha",5),"")
- Output:
"*****" "hahahahaha"
Phixmonti
def rep /# s n -- s #/
"" swap
for drop
over chain
endfor
nip
enddef
"ha" 5 rep print
Same result (simple character):
65 5 rep
65 5 repeat
'A' 5 repeat
PHP
str_repeat("ha", 5)
PicoLisp
(pack (need 5 "ha"))
-> "hahahahaha"
or:
(pack (make (do 5 (link "ha"))))
-> "hahahahaha"
Pike
"ha"*5;
PL/I
/* To repeat a string a variable number of times: */
s = repeat('ha', 4);
/* or */
s = copy('ha', 5);
/* To repeat a single character a fixed number of times: */
s = (5)'h'; /* asigns 'hhhhh' to s. */
Plain English
To run:
Start up.
Put "ha" into a string.
Append the string to itself given 5.
Write the string on the console.
Fill another string with the asterisk byte given 5.
Write the other string on the console.
Wait for the escape key.
Shut down.
To append a string to itself given a number:
If the number is less than 1, exit.
Privatize the string.
Privatize the number.
Subtract 1 from the number.
Append the string to the original string given the number.
- Output:
hahahahaha *****
Plorth
"ha" 5 *
PostScript
% the comments show the stack content after the line was executed
% where rcount is the repeat count, "o" is for orignal,
% "f" is for final, and iter is the for loop variable
%
% usage: rcount ostring times -> fstring
/times {
dup length dup % rcount ostring olength olength
4 3 roll % ostring olength olength rcount
mul dup string % ostring olength flength fstring
4 1 roll % fstring ostring olength flength
1 sub 0 3 1 roll % fstring ostring 0 olength flength_minus_one
{ % fstring ostring iter
1 index 3 index % fstring ostring iter ostring fstring
3 1 roll % fstring ostring fstring iter ostring
putinterval % fstring ostring
} for
pop % fstring
} def
PowerBASIC
MSGBOX REPEAT$(5, "ha")
PowerShell
"ha" * 5 # ==> "hahahahaha"
Processing
void setup() {
String rep = repeat("ha", 5);
println(rep);
}
String repeat(String str, int times) {
// make an array of n chars,
// replace each char with str,
// and return as a new String
return new String(new char[times]).replace("\0", str);
}
Processing Python mode
def setup():
rep = repeat("ha", 5)
println(rep)
def repeat(s, times):
return s * times
Prolog
%repeat(Str,Num,Res).
repeat(Str,1,Str).
repeat(Str,Num,Res):-
Num1 is Num-1,
repeat(Str,Num1,Res1),
string_concat(Str, Res1, Res).
alternative using DCG strings
This tail-recursive DCG implemention is more efficient than anything using lists:append .
:- system:set_prolog_flag(double_quotes,chars) .
repeat(SOURCEz0,COUNT0,TARGETz)
:-
prolog:phrase(repeat(SOURCEz0,COUNT0),TARGETz)
.
%! repeat(SOURCEz0,COUNT0)//2
repeat(_SOURCEz0_,0)
-->
! ,
[]
.
repeat(SOURCEz0,COUNT0)
-->
SOURCEz0 ,
{ COUNT is COUNT0 - 1 } ,
repeat(SOURCEz0,COUNT)
.
- Output:
/* ?- repeat("ha",5,TARGETz) . TARGETz = [h, a, h, a, h, a, h, a, h, a]. ?- */
:- begin_tests(basic) . :- system:set_prolog_flag(double_quotes,chars) . test('1',[]) :- repeat("a",2,"aa") . test('2',[]) :- repeat("ha",2,"haha") . test('3',[]) :- repeat("ha",3,"hahaha") . test('4',[]) :- repeat("",3,"") . test('5',[]) :- repeat("ha",0,"") . test('6',[]) :- repeat("ha",1,"ha") . :- end_tests(basic) .
Pure
str_repeat is defined by pattern-matching: repeating any string 0 times results in the empty string; while repeating it more than 0 times results in the concatenation of the string and (n-1) further repeats.
> str_repeat 0 s = "";
> str_repeat n s = s + (str_repeat (n-1) s) if n>0;
> str_repeat 5 "ha";
"hahahahaha"
>
You can define str_repeat using infinite lazy list (stream).
str_repeat n::int s::string = string $ take n $ cycle (s:[]);
PureBasic
Procedure.s RepeatString(count, text$=" ")
Protected i, ret$=""
For i = 1 To count
ret$ + text$
Next
ProcedureReturn ret$
EndProcedure
Debug RepeatString(5, "ha")
Python
"ha" * 5 # ==> "hahahahaha"
"Characters" are just strings of length one.
the other way also works:
5 * "ha" # ==> "hahahahaha"
Using a Function
def repeat(s, times):
return s * times
print(repeat("ha", 5))
- Output:
hahahahaha
Using Lambda
x = lambda a: a * 5
print(x("ha"))
- Output:
hahahahaha
Quackery
$ "ha" 5 of echo$
Output:
hahahahaha
R
strrep("ha", 5)
Racket
#lang racket
;; fast
(define (string-repeat n str)
(string-append* (make-list n str)))
(string-repeat 5 "ha") ; => "hahahahaha"
To repeat a single character:
(make-string 5 #\*) => "*****"
Raku
(formerly Perl 6)
print "ha" x 5
(Note that the x
operator isn't quite the same as in Perl 5: it now only creates strings. To create lists, use xx
.)
RapidQ
'For a single char
showmessage String$(10, "-")
'For strings with more than one char
function Repeat$(Expr as string, Count as integer) as string
dim x as integer
for x = 1 to Count
Result = Result + Expr
next
end function
showmessage Repeat$("ha", 5)
REALbasic
Function Repeat(s As String, count As Integer) As String
Dim output As String
For i As Integer = 0 To count
output = output + s
Next
Return output
End Function
REBOL
head insert/dup "" "ha" 5
Red
>> str: "Add duplicates to string"
>> insert/dup str "ha" 3
== "hahahaAdd duplicates to string"
>> insert/dup tail str "ha" 3
== "hahahaAdd duplicates to stringhahaha"
ReScript
Js.log(Js.String2.repeat("ha", 5))
Retro
with strings'
: repeatString ( $n-$ )
1- [ dup ] dip [ over prepend ] times nip ;
"ha" 5 repeatString
REXX
Since the REXX language only supports the "character" type, it's not surprising that there are so many ways to skin a cat.
/*REXX program to show various ways to repeat a string (or repeat a single char).*/
/*all examples are equivalent, but not created equal.*/
/*───────────────────────────────────────────*/
y='ha'
z=copies(y,5)
/*───────────────────────────────────────────*/
z=copies( 'ha', 5 )
/*───────────────────────────────────────────*/
y='ha'
z=y||y||y||y||y
/*───────────────────────────────────────────*/
y='ha'
z=y || y || y || y || y /*same as previous, but the "big sky" version*/
/*───────────────────────────────────────────*/
y='ha'
z=''
do 5
z=z||y
end
/*───────────────────────────────────────────*/
y="ha"
z=
do 5
z=z||y
end
/*───────────────────────────────────────────*/
y="ha"
z=
do i=101 to 105
z=z||y
end
/*───────────────────────────────────────────*/
y='+'
z=left('',5,y)
/*───────────────────────────────────────────*/
y='+'
z=right('',5,y)
/*───────────────────────────────────────────*/
y='+'
z=substr('',1,5,y)
/*───────────────────────────────────────────*/
y='+'
z=center('',5,y)
/*───────────────────────────────────────────*/
y='+'
z=centre('',5,y)
/*───────────────────────────────────────────*/
y='+'
z=space('',5,y)
/*───────────────────────────────────────────*/
y='+'
z=translate('@@@@@',y,"@")
/*───────────────────────────────────────────*/
y='abcdef'
z=five(y)
exit
five: procedure expose y; parse arg g
if length(g)>=5*length(y) then return g
return five(y||g)
/*───────────────────────────────────────────*/
y='something wicked this way comes.'
z=y||y||y||y||y||y||y||y||y||y||y||y|\y||y||y
z=left(z,5*length(y))
/*───────────────────────────────────────────*/
y='+'
z=copies('',5,y)
/*───────────────────────────────────────────*/
y='+'
z=lower('',1,5,y)
/*───────────────────────────────────────────*/
y='+'
z=lower('',,5,y)
/*───────────────────────────────────────────*/
z='+'
z=upper('',1,5,y)
/*───────────────────────────────────────────*/
z=upper('',,5,y)
/*───────────────────────────────────────────*/
y='charter bus.'
z='*****'
z=changestr('*',z,y)
/*───────────────────────────────────────────*/
y='what the hey!'
z=
do until length(z)==5*length(y)
z=z||y
end
/*───────────────────────────────────────────*/
y='what the hey!'
z=
do until length(z)==5*length(y)
z=insert(z,0,y)
end
/*───────────────────────────────────────────*/
y='yippie ki yay'
z=
do i=1 by 5 for 5
z=overlay(y,z,i)
end
/*───────────────────────────────────────────*/
y='+'
z=justify('',5,y)
/*───────────────────────────────────────────*/
whatever_this_variable_is_____it_aint_referenced_directly= 'boy oh boy.'
z=; signal me; me:
do 5
z=z||strip(subword(sourceline(sigl-1),2),,"'")
end
/*───────────────────────────────────────────*/
y="any more examples & the angry townfolk with pitchforks will burn the castle."
parse value y||y||y||y||y with z
exit /*stick a fork in it, we're done.*/
Some older REXXes don't have a changestr bif, so one is included here ──► CHANGESTR.REX.
Ring
Copy("ha" , 5) # ==> "hahahahaha"
RPL
≪ "" 1 5 START "ha" + NEXT ≫ EVAL
- Output:
1: "hahahahaha"
Ruby
"ha" * 5 # ==> "hahahahaha"
Run BASIC
a$ = "ha "
for i = 1 to 5
a1$ = a1$ + a$
next i
a$ = a1$
print a$
Rust
std::iter::repeat("ha").take(5).collect::<String>(); // ==> "hahahahaha"
Since 1.16:
"ha".repeat(5); // ==> "hahahahaha"
Scala
"ha" * 5 // ==> "hahahahaha"
Scheme
(define (string-repeat n str)
(apply string-append (vector->list (make-vector n str))))
with SRFI 1:
(define (string-repeat n str)
(fold string-append "" (make-list n str)))
(string-repeat 5 "ha") ==> "hahahahaha"
To repeat a single character:
(make-string 5 #\*)
Scratch
This example requires making variables named "String", "Count", and "Repeated" first.
sed
Number of ampersands indicates number of repetitions.
$ echo ha | sed 's/.*/&&&&&/'
hahahahaha
Seed7
$ include "seed7_05.s7i";
const proc: main is func
begin
writeln("ha" mult 5);
end func;
Output:
hahahahaha
SenseTalk
put "Ho!" repeated 3 times
put "Merry" repeated to length 12
Output:
Ho!Ho!Ho! MerryMerryMe
Sidef
'ha' * 5; # ==> 'hahahahaha'
Sinclair ZX81 BASIC
Works with 1k of RAM. This program defines a subroutine that expects to find a string and a number of times to repeat it; but all it then does is loop and concatenate, so making it a separate subroutine is arguably overkill.
10 LET S$="HA"
20 LET N=5
30 GOSUB 60
40 PRINT T$
50 STOP
60 LET T$=""
70 FOR I=1 TO N
80 LET T$=T$+S$
90 NEXT I
100 RETURN
Smalltalk
If n is a small constant, then simply concatenating n times will do; for example, n=5::
v := 'ha'.
v,v,v,v,v
By creating a collection of n 'ha', and joining them to a string:
((1 to: n) collect: [:x | 'ha']) joinUsing: ''.
or:
(Array new:n withAll:'ha') asStringWith:''.
By creating a WriteStream, and putting N times the string 'ha' into it:
ws := '' writeStream.
n timesRepeat: [ws nextPutAll: 'ha'].
ws contents.
alternatively:
(String streamContents:[:ws | n timesRepeat: [ws nextPutAll: 'ha']])
all evaluate to:
hahahahaha
A string containing a repeated character is generated with:
String new:n withAll:$*
(String new:n) atAllPut:$*
SNOBOL4
output = dupl("ha",5)
end
Sparkling
spn:3> repeat("na", 8) .. " Batman!"
= nananananananana Batman!
SQL
select rpad('', 10, 'ha')
SQL PL
VALUES REPEAT('ha', 5);
VALUES RPAD('', 10, 'ha');
Output:
db2 -t db2 => VALUES REPEAT('ha', 5); 1 ---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- hahahahaha 1 record(s) selected. db2 => VALUES RPAD('', 10, 'ha'); 1 ---------- hahahahaha 1 record(s) selected.
Standard ML
fun string_repeat (s, n) =
concat (List.tabulate (n, fn _ => s))
;
testing in the interpreter:
- string_repeat ("Hiuoa", 3) ;
val it = "HiuoaHiuoaHiuoa" : string
To repeat a single character:
fun char_repeat (c, n) =
implode (List.tabulate (n, fn _ => c))
;
Stata
. scalar a="ha"
. scalar b=a*5
. display b
hahahahaha
Suneido
'ha'.Repeat(5) --> "hahahahaha"
'*'.Repeat(5) --> "*****"
Swift
The Builtin Way
print(String(repeating:"*", count: 5))
- Output:
*****
Functions
func * (left:String, right:Int) -> String {
return String(repeating:left, count:right)
}
print ("HA" * 5)
- Output:
HAHAHAHAHA
Extensions
Using extensions to do the repetition which makes for an easier syntax when repeating Strings, and using String.extend() to get faster evaluation.
extension String {
// Slower version
func repeatString(n: Int) -> String {
return Array(count: n, repeatedValue: self).joinWithSeparator("")
}
// Faster version
// benchmarked with a 1000 characters and 100 repeats the fast version is approx 500 000 times faster :-)
func repeatString2(n:Int) -> String {
var result = self
for _ in 1 ..< n {
result.appendContentsOf(self) // Note that String.appendContentsOf is up to 10 times faster than "result += self"
}
return result
}
}
print( "ha".repeatString(5) )
print( "he".repeatString2(5) )
- Output:
hahahahaha hehehehehe
To repeat a single character:
String(count:5, repeatedValue:"*" as Character)
Note that using the String version on a string of 1 Character, or the repeat single Character version is timewise close to the same. No point in using the Character version for efficiency (tested with repeating up to 100 000 times).
Bitwise Iterative Version
The following version is an enhanced version of the recursive ActionScript, where we're using bit operation along with iterative doubling of the string to get to the correctly repeated version of the text in the most effective manner without recursion. When benchmarked against the plain iterative version in previous section, this version is marginally better, but only my a very small percentage. The critical factor for making the repeat function effective when using larger strings (1000 characters) and multiple repeats (1000 repeats :-) ) was to to exchange the '+=' with 'String.extend' method.
extension String {
func repeatBiterative(count: Int) -> String {
var reduceCount = count
var result = ""
var doubled = self
while reduceCount != 0 {
if reduceCount & 1 == 1 {
result.appendContentsOf(doubled)
}
reduceCount >>= 1
if reduceCount != 0 {
doubled.appendContentsOf(doubled)
}
}
return result
}
}
"He".repeatBiterative(5)
- Output:
"HeHeHeHeHe"
Tailspin
'$:1..5 -> 'ha';' -> !OUT::write
- Output:
hahahahaha
Tcl
string repeat "ha" 5 ;# => hahahahaha
TorqueScript
--Eepos
function strRep(%str,%int)
{
for(%i = 0; %i < %int; %i++)
{
%rstr = %rstr@%str;
}
return %rstr;
}
Tosh
when flag clicked
set String to "meow"
set Count to 4
set Repeated to ""
repeat Count
set Repeated to (join (Repeated) (String))
end
stop this script
Transact-SQL
select REPLICATE( 'ha', 5 )
TUSCRIPT
$$ MODE TUSCRIPT
repeatstring=REPEAT ("ha",5)
UNIX Shell
Using printf
printf "ha"%.0s {1..5}
With ksh93 and zsh, the count can vary.
i=5
printf "ha"%.0s {1..$i}
With bash, {1..$i}
fails, because brace expansion happens before variable substitution. The fix uses eval
.
i=5
eval "printf 'ha'%.0s {1..$i}"
For the general case, one must escape any % or \ characters in the string, because printf
would interpret those characters.
reprint() {
typeset e="$(sed -e 's,%,%%,g' -e 's,\\,\\\\,g' <<<"$1")"
eval 'printf "$e"%.0s '"{1..$2}"
}
reprint '% ha \' 5
Using repeat
len=12; str='='
repeat $len printf "$str"
Using head -c
head -c
is a GNU extension, so it only works with those systems. (Also, this script can only repeat a single character.)
width=72; char='='
head -c ${width} < /dev/zero | tr '\0' "$char"
Ursala
#import nat
repeat = ^|DlSL/~& iota
#cast %s
example = repeat('ha',5)
output:
'hahahahaha'
Vala
Repeat a string 5 times:
string s = "ha";
string copy = "";
for (int x = 0; x < 5; x++)
copy += s;
Fill a string with a char N times:
string s = string.nfill(5, 'c');
VBA
Repeat a string
Public Function RepeatStr(aString As String, aNumber As Integer) As String
Dim bString As String, i As Integer
bString = ""
For i = 1 To aNumber
bString = bString & aString
Next i
RepeatStr = bString
End Function
Debug.Print RepeatStr("ha", 5)
- Output:
hahahahaha
Note: "String(5, "ha") in VBA produces "hhhhh" (only the first character is repeated)!
An alternative method:
Public Function RepeatString(stText As String, iQty As Integer) As String
RepeatString = Replace(String(iQty, "x"), "x", stText)
End Function
Repeat a character
Debug.Print String(5, "x")
- Output:
xxxxx
VBScript
' VBScript has a String() function that can repeat a character a given number of times
' but this only works with single characters (or the 1st char of a string):
WScript.Echo String(10, "123") ' Displays "1111111111"
' To repeat a string of chars, you can use either of the following "hacks"...
WScript.Echo Replace(Space(10), " ", "Ha")
WScript.Echo Replace(String(10, "X"), "X", "Ha")
Vedit macro language
Ins_Text("ha", COUNT, 5)
Visual Basic
Repeat a string
Public Function StrRepeat(s As String, n As Integer) As String
Dim r As String, i As Integer
r = ""
For i = 1 To n
r = r & s
Next i
StrRepeat = r
End Function
Debug.Print StrRepeat("ha", 5)
- Output:
hahahahaha
An alternative method:
Public Function StrRepeat(sText As String, n As Integer) As String
StrRepeat = Replace(String(n, "*"), "*", sText)
End Function
Repeat a character
Debug.Print String(5, "x")
- Output:
xxxxx
Visual Basic .NET
Repeat a string
Debug.Print(Replace(Space(5), " ", "Ha"))
- Output:
HaHaHaHaHa
Repeat a character
Debug.Print(StrDup(5, "x"))
Debug.Print("".PadRight(5, "x"))
Debug.Print("".PadLeft(5, "x"))
- Output:
xxxxx xxxxx xxxxx
Visual FoxPro
Use the built in function REPLICATE(string, number):
? REPLICATE("HO", 3)
produces
HOHOHO
V (Vlang)
// Repeat a string, in V
// Tectonics: v run repeat-a-string.v
module main
import strings
// starts here
pub fn main() {
// A strings module function to repeat strings
println(strings.repeat_string("ha", 5))
// Another strings module function to repeat a byte
// This indexes the string to get the first byte of the rune array
println(strings.repeat("*"[0], 5))
}
- Output:
prompt$ v run rosetta/repeat-a-string.v hahahahaha *****
VBScript
replace(string(5,"@"),"@","hello")
- Output:
hellohellohellohellohello
Wart
def (s * n) :case (string? s)
with outstring
repeat n
pr s
("ha" * 5)
=> "hahahahaha"
Wortel
@join "" @rep 5 "ha" ; returns "hahahahaha"
As a function:
^(\@join "" @rep)
Wren
System.print("ha" * 5)
- Output:
hahahahaha
XPL0
cod T=12; int I; for I gets 1,5 do T(0,"ha")
- Output:
hahahahaha
Yorick
array("ha", 5)(sum)
Z80 Assembly
PrintChar equ &BB5A ;Amstrad CPC BIOS call, prints the ascii code in the accumulator to the screen.
org &8000
ld b,5 ; repeat 5 times
loop:
call PrintImmediate
byte "ha",0
djnz loop
ret ; return to basic
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
PrintImmediate:
pop hl ; get the return address into HL, it's the start of the embedded string.
call PrintString
; inc hl ; if your strings are null-terminated you can omit this, since a 0 equals the "NOP" instruction
jp (hl) ; acts as a ret, returning execution to the instruction just after the embedded string.
PrintString:
ld a,(hl) ; read in a character from the string
or a ; if your strings are null-terminated you can use this as a shortcut, otherwise use the compare instruction
ret z ; exit once the terminator is reached.
call PrintChar ; BIOS call, all regs are preserved.
inc hl ; next char
jr PrintString ; back to start.
- Output:
hahahahaha
zig
At compile-time:
const laugh = "ha" ** 5;
Note that to achieve this at run-time in zig (in order to avoid hidden overflows) you must manage the memory yourself.
const std = @import("std");
const warn = std.debug.warn;
const Allocator = std.mem.Allocator;
fn repeat(s: []const u8, times: u16, allocator: *Allocator) ![]u8 {
const repeated = try allocator.alloc(u8, s.len*times);
var i: usize = 0;
while (i < s.len*times) : (i += 1) {
repeated[i] = s[i % 2];
}
return repeated;
}
pub fn main() !void {
const allocator = std.debug.global_allocator;
const ex = try repeat("ha", 5, allocator);
defer allocator.free(ex);
}
zkl
Same as Ruby
"ha" * 5 # --> "hahahahaha"
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- Pages with too many expensive parser function calls