Text between
- Task
Get the text in a string that occurs between a start and end delimiter. Programs will be given a search string, a start delimiter string, and an end delimiter string. The delimiters will not be unset, and will not be the empty string.
The value returned should be the text in the search string that occurs between the first occurrence of the start delimiter (starting after the text of the start delimiter) and the first occurrence of the end delimiter after that.
If the start delimiter is not present in the search string, a blank string should be returned.
If the end delimiter is not present after the end of the first occurrence of the start delimiter in the search string, the remainder of the search string after that point should be returned.
There are two special values for the delimiters. If the value of the start delimiter is "start", the beginning of the search string will be matched. If the value of the end delimiter is "end", the end of the search string will be matched.
Example 1. Both delimiters set
Text: "Hello Rosetta Code world" Start delimiter: "Hello " End delimiter: " world" Output: "Rosetta Code"
Example 2. Start delimiter is the start of the string
Text: "Hello Rosetta Code world" Start delimiter: "start" End delimiter: " world" Output: "Hello Rosetta Code"
Example 3. End delimiter is the end of the string
Text: "Hello Rosetta Code world" Start delimiter: "Hello" End delimiter: "end" Output: "Rosetta Code world"
Example 4. End delimiter appears before and after start delimiter
Text: "</div><div style=\"chinese\">你好嗎</div>" Start delimiter: "<div style=\"chinese\">" End delimiter: "</div>" Output: "你好嗎"
Example 5. End delimiter not present
Text: "<text>Hello <span>Rosetta Code</span> world</text><table style=\"myTable\">" Start delimiter: "<text>" End delimiter: "<table>" Output: "Hello <span>Rosetta Code</span> world</text><table style=\"myTable\">"
Example 6. Start delimiter not present
Text: "<table style=\"myTable\"><tr><td>hello world</td></tr></table>" Start delimiter: "<table>" End delimiter: "</table>" Output: ""
Example 7. Multiple instances of end delimiter after start delimiter (match until the first one)
Text: "The quick brown fox jumps over the lazy other fox" Start delimiter: "quick " End delimiter: " fox" Output: "brown"
Example 8. Multiple instances of the start delimiter (start matching at the first one)
Text: "One fish two fish red fish blue fish" Start delimiter: "fish " End delimiter: " red" Output: "two fish"
Example 9. Start delimiter is end delimiter
Text: "FooBarBazFooBuxQuux" Start delimiter: "Foo" End delimiter: "Foo" Output: "BarBaz"
AppleScript
<lang applescript> my text_between("Hello Rosetta Code world", "Hello ", " world")
on text_between(this_text, start_text, end_text) set return_text to "" try if (start_text is not "start") then set AppleScript's text item delimiters to start_text set return_text to text items 2 thru end of this_text as string else set return_text to this_text end if if (end_text is not "end") then set AppleScript's text item delimiters to end_text set return_text to text item 1 of return_text as string set AppleScript's text item delimiters to "" end if end try set AppleScript's text item delimiters to ""
return return_text end text_between </lang>
C
<lang c> /*
* textBetween: Gets text between two delimiters */
char* textBetween(char* thisText, char* startText, char* endText, char* returnText) { //printf("textBetween\n");
char* startPointer = NULL; int stringLength = 0;
char* endPointer = NULL; int endLength = 0;
if (strstr(startText, "start") != NULL) { // Set the beginning of the string startPointer = thisText; } else { startPointer = strstr(thisText, startText);
if (startPointer != NULL)
{
startPointer = startPointer + strlen(startText);
}
} // end if the start delimiter is "start"
if (startPointer != NULL)
{
if (strstr(endText, "end") != NULL) { // Set the end of the string endPointer = thisText; endLength = 0; } else { endPointer = strstr(startPointer, endText); endLength = (int)strlen(endPointer); } // end if the end delimiter is "end"
stringLength = strlen(startPointer) - endLength;
if (stringLength == 0)
{
returnText = ""; startPointer = NULL;
} else {
// Copy characters between the start and end delimiters
strncpy(returnText,startPointer, stringLength);
returnText[stringLength++] = '\0'; }
} else {
//printf("Start pointer not found\n"); returnText = "";
} // end if the start pointer is not found return startPointer;
} // end textBetween method</lang>
Haskell
<lang Haskell>import Data.Text (Text, breakOn, pack, stripPrefix, unpack) import Data.List (intercalate) import Control.Arrow ((***))
-- TEXT BETWEEN ----------------------------------------------------------- textBetween :: (Either String Text, Either String Text) -> Text -> Text textBetween (s, e) txt =
let stet t = (Just . const t)
prune f t = f . flip breakOn t
-- Text up to and including any start delimiter dropped
mb =
either (stet txt) (stripPrefix <*> prune snd txt) s >>=
-- Residue up to any end delimiter (or if none found, to end)
(\lp -> either (stet lp) (Just . prune fst lp) e)
in case mb of
Just x -> x
_ -> pack []
-- TESTS ------------------------------------------------------------------ samples :: [Text] samples =
pack <$> [ "Hello Rosetta Code world"
, "
" , "<text>Hello Rosetta Code world</text>
" , "| hello world |
"
]
delims :: [(Either String Text, Either String Text)] delims =
(wrap *** wrap) <$>
[ ("Hello ", " world")
, ("start", " world")
, ("Hello", "end")
, ("
") , ("<text>", "
") , ("<text>", "")
]
wrap :: String -> Either String Text wrap x =
pack <$> if x `elem` ["start", "end"] then Left x else Right x
main :: IO () main = do
mapM_ print $ flip textBetween (head samples) <$> take 3 delims
(putStrLn . unlines) $
zipWith
(\d t -> intercalate (unpack $ textBetween d t) ["\"", "\""])
(drop 3 delims)
(tail samples)</lang>
- Output:
"Rosetta Code" "Hello Rosetta Code" " Rosetta Code world" "你好吗" "Hello <span>Rosetta Code</span> world</text><table style="myTable">" ""
Java
javac textBetween.java java -cp . textBetween "hello Rosetta Code world" "hello " " world"
<lang java> public class textBetween {
/*
* textBetween: Get the text between two delimiters
*/
static String textBetween(String thisText, String startString, String endString)
{
String returnText = "";
int startIndex = 0;
int endIndex = 0;
if (startString.equals("start"))
{
startIndex = 0;
} else {
startIndex = thisText.indexOf(startString);
if (startIndex < 0) { return ""; } else { startIndex = startIndex + startString.length(); }
}
if (endString.equals("end"))
{
endIndex = thisText.length();
} else {
endIndex = thisText.indexOf(endString);
if (endIndex <= 0)
{
return "";
} else {
} } returnText = thisText.substring(startIndex,endIndex); return returnText; } // end method textBetween
/**
* Main method
*/
public static void main(String[] args)
{
String thisText = args[0];
String startDelimiter = args[1];
String endDelimiter = args[2];
String returnText = "";
returnText = textBetween(thisText, startDelimiter, endDelimiter);
System.out.println(returnText);
} // end method main
} // end class TextBetween </lang>
JavaScript
<lang javascript> function textBetween(thisText, startString, endString) { if (thisText == undefined) { return ""; }
var start_pos = 0; if (startString != 'start') { start_pos = thisText.indexOf(startString);
// If the text does not contain the start string, return a blank string if (start_pos < 0) { return ; }
// Skip the first startString characters start_pos = start_pos + startString.length; }
var end_pos = thisText.length; if (endString != 'end') { end_pos = thisText.indexOf(endString,start_pos); }
// If the text does not have the end string after the start string, return the whole string after the start if (end_pos < start_pos) { end_pos = thisText.length; }
var newText = thisText.substring(start_pos,end_pos);
return newText; } // end textBetween </lang>
Kotlin
In the third example, I've assumed that the start delimiter should be "Hello " (not "Hello") to match the required output. <lang scala>// version 1.2.10
fun String.textBetween(start: String, end: String): String {
require(!start.isEmpty() && !end.isEmpty()) if (this.isEmpty()) return this val s = if (start == "start") 0 else this.indexOf(start) if (s == -1) return "" val si = if (start == "start") 0 else s + start.length val e = if (end == "end") this.length else this.indexOf(end, si) if (e == -1) return this.substring(si) return this.substring(si, e)
}
fun main(args: Array<String>) {
val texts = listOf(
"Hello Rosetta Code world",
"Hello Rosetta Code world",
"Hello Rosetta Code world",
"
", "<text>Hello Rosetta Code world</text>
", "| hello world |
",
"The quick brown fox jumps over the lazy other fox",
"One fish two fish red fish blue fish",
"FooBarBazFooBuxQuux"
)
val startEnds = listOf(
"Hello " to " world",
"start" to " world",
"Hello " to "end",
"
", "<text>" to "
", "",
"quick " to " fox",
"fish " to " red",
"Foo" to "Foo"
)
for ((i, text) in texts.withIndex()) {
println("Text: \"$text\"")
val (s, e) = startEnds[i]
println("Start delimiter: \"$s\"")
println("End delimiter: \"$e\"")
val b = text.textBetween(s, e)
println("Output: \"$b\"\n")
}
}</lang>
- Output:
Text: "Hello Rosetta Code world" Start delimiter: "Hello " End delimiter: " world" Output: "Rosetta Code" Text: "Hello Rosetta Code world" Start delimiter: "start" End delimiter: " world" Output: "Hello Rosetta Code" Text: "Hello Rosetta Code world" Start delimiter: "Hello " End delimiter: "end" Output: "Rosetta Code world" Text: "</div><div style="chinese">你好嗎</div>" Start delimiter: "<div style="chinese">" End delimiter: "</div>" Output: "你好嗎" Text: "<text>Hello <span>Rosetta Code</span> world</text><table style="myTable">" Start delimiter: "<text>" End delimiter: "<table>" Output: "Hello <span>Rosetta Code</span> world</text><table style="myTable">" Text: "<table style="myTable"><tr><td>hello world</td></tr></table>" Start delimiter: "<table>" End delimiter: "</table>" Output: "" Text: "The quick brown fox jumps over the lazy other fox" Start delimiter: "quick " End delimiter: " fox" Output: "brown" Text: "One fish two fish red fish blue fish" Start delimiter: "fish " End delimiter: " red" Output: "two fish" Text: "FooBarBazFooBuxQuux" Start delimiter: "Foo" End delimiter: "Foo" Output: "BarBaz"
Perl 6
It seems somewhat pointless to write a general purpose routine to do text matching as built-in primitives can do so more flexibly and concisely, but whatever.
<lang perl6>sub text-between ( $text, $start, $end ) {
return $/»[0]».Str if $text ~~ m:g/ $start (.*?) $end /; []
}
- Testing
my $text = 'Hello Rosetta Code world';
- String start and end delimiter
put '1> ', $text.&text-between( 'Hello ', ' world' );
- Regex string start delimiter
put '2> ', $text.&text-between( rx/^/, ' world' );
- Regex string end delimiter
put '3> ', $text.&text-between( 'Hello', rx/$/ );
- Return all matching strings when multiple matches are possible
put '4> ', join ',', $text.&text-between( 'e', 'o' );
- End delimiter only valid after start delimiter
put '5> ', '
'\ .&text-between( '
' );
- End delimiter or string end if not found
put '6> ', '<text>Hello Rosetta Code world</text>
'\ .&text-between( '<text>', rx/'- Start delimiter not found, return blank string
| hello world |
'\ .&text-between( '
', '' );</lang>
- Output:
1> Rosetta Code 2> Hello Rosetta Code 3> Rosetta Code world 4> ll,tta C, w 5> 你好嗎 6> Hello <span>Rosetta Code</span> world</text><table style="myTable"> 7>
PHP
http://localhost/textBetween.php?thisText=hello%20Rosetta%20Code%20world&start=hello%20&end=%20world
<lang php> <?php function text_between($string, $start, $end) {
//$string = " ".$string;
$startIndex = strpos($string,$start);
if ($start == "start")
{
$startIndex = 0;
} else {
if ($startIndex == 0)
{
return "Start text not found";
}
}
if ($end == "end")
{
$endIndex=strlen($string);
$resultLength = $endIndex - $startIndex;
} else {
$resultLength = strpos($string,$end,$startIndex) - $startIndex; }
if ($start != "start")
{
$startIndex += strlen($start); }
if ($resultLength <= 0)
{
return "End text not found";
}
return substr($string,$startIndex,$resultLength);
}
$thisText=$_GET["thisText"]; $startDelimiter=$_GET["start"]; $endDelimiter=$_GET["end"];
$returnText = text_between($thisText, $startDelimiter, $endDelimiter);
print_r($returnText); ?> </lang>
Python
<lang python>
- !/usr/bin/env python
from sys import argv
- textBetween in python
- Get the text between two delimiters
- Usage:
- python textBetween.py "hello Rosetta Code world" "hello " " world"
def textBetween( thisText, startString, endString ):
try:
if startString is 'start':
startIndex = 0
else:
startIndex = thisText.index( startString )
if not (startIndex >= 0):
return 'Start delimiter not found'
else:
startIndex = startIndex + len( startString )
returnText = thisText[startIndex:]
if endString is 'end': return returnText else: endIndex = returnText.index( endString )
if not (endIndex >= 0):
return 'End delimiter not found'
else:
returnText = returnText[:endIndex]
return returnText
except ValueError:
return "Value error"
script, first, second, third = argv
thisText = first startString = second endString = third
print textBetween( thisText, startString, endString ) </lang>
REXX
<lang rexx>Say 'Using the string Hello Rosetta Code world:' Call test 'Hello Rosetta Code world','Hello ',' world' Call test 'Hello Rosetta Code world','<start>',' world' Call test 'Hello Rosetta Code world','Hello','<end>' Call test 'Hello Rosetta Code world','Hello Rosetta ','Code world' Call test 'Hello Rosetta Code world','Hello Rosetta','Code world' Call test 'Hello Rosetta Code world','Code','Hello' Call test 'Hello Rosetta Code world','Hello Rosetta Code','Code world' Call test 'Hello Rosetta Code world','Goodbye','Code world' Exit
test: Procedure
Parse Arg t,s,e res=text_between(t,s,e) Say ' text between' "'"s"'" 'and' "'"e"'" 'is' "'"res"'" Return
text_between: Procedure
Parse Arg this_text, start_text, end_text
If start_text='<start>' Then
rest=this_text
Else Do
s=pos(start_text,this_text)
If s>0 Then
rest=substr(this_text,s+length(start_text))
Else
Return this_text
End
If end_text='<end>' Then
Return rest
Else Do
e=pos(end_text,rest)
If e=0 Then
Return this_text
Return left(rest,e-1)
End</lang>
- Output:
Using the string 'Hello Rosetta Code world': text between 'Hello ' and ' world' is 'Rosetta Code' text between '<start>' and ' world' is 'Hello Rosetta Code' text between 'Hello' and '<end>' is ' Rosetta Code world' text between 'Hello Rosetta ' and 'Code world' is '' text between 'Hello Rosetta' and 'Code world' is ' ' text between 'Code' and 'Hello' is 'Hello Rosetta Code world' text between 'Hello Rosetta Code' and 'Code world' is 'Hello Rosetta Code world' text between 'Goodbye' and 'Code world' is 'Hello Rosetta Code world'
Ruby
Test <lang ruby> class String
def textBetween startDelimiter, endDelimiter if (startDelimiter == "start") then startIndex = 0 else startIndex = self.index(startDelimiter) + startDelimiter.length end if (startIndex == nil) then return "Start delimiter not found" end thisLength = self.length returnText = self[startIndex, thisLength] if (endDelimiter == "end") then endIndex = thisLength else endIndex = returnText.index(endDelimiter) end if (endIndex == nil) then return "End delimiter not found" end returnText = returnText[0, endIndex] return returnText end
end
thisText = ARGV[0] startDelimiter = ARGV[1] endDelimiter = ARGV[2]
- puts thisText
- puts startDelimiter
- puts endDelimiter
returnText = thisText.textBetween(startDelimiter, endDelimiter)
puts returnText </lang>
UNIX Shell
This implementation creates no processes/subshells in modern shells (e.g. shells in which 'echo' and '[' are builtins). It modifies/leaks no global state other than the "text_between" function's name. Its behavior is not changed by the presence or absence of common shell options (e.g. "-e", "-u", "pipefail", or POSIX compatibility mode) or settings (e.g. "IFS").
This can be made to work with ksh (93) by removing all uses of the "local" keyword, though this will cause it to modify global variables.
The "hard" assertions when unpacking the arguments to the "text_between" function reflect the assumptions in the requirements for this problem: that null/empty arguments will never be provided. If any empty arguments are given, the interpreter running this function will exit after printing an error. If this function is invoked without a subshell, that will crash the invoking program as well. In practical use, that may not be desirable, in which case the ":?" assertions should be replaced with less harsh conditional-unpack code (e.g. if [ -z "${1:-}" ]; then echo "Invalid input!" && return 127; else local var="$1"; fi).
<lang bash>text_between() { local search="${1:?Search text not provided}" local start_str="${2:?Start text not provided}" local end_str="${3:?End text not provided}" local temp=
if [ "$start_str" != "start" ]; then # $temp will be $search with everything before the first occurrence of # $start_str (inclusive) removed, searching from the beginning. temp="${search#*$start_str}" # If the start delimiter wasn't found, return an empty string. # Comparing length rather than string equality because character # comparison is not necessary here. if [ "${#temp}" -eq "${#search}" ]; then search= else search="$temp" fi fi
if [ "$end_str" = "end" ]; then echo "$search" else # Output will be $search with everything after the last occurrence of # $end_str (inclusive) removed, searching from the end. echo "${search%%$end_str*}" fi return 0 }
text_between "Hello Rosetta Code world" "Hello " " world" text_between "Hello Rosetta Code world" "start" " world" text_between "Hello Rosetta Code world" "Hello " "end"</lang>
zkl
<lang zkl>fcn getText(text,start,end){
s = (if((s:=text.find(start))==Void) 0 else s + start.len()); e = (if((e:=text.find(end,s))==Void) text.len() else e); text[s,e - s]
} getText("Hello Rosetta Code world","Hello "," world").println(); getText("Hello Rosetta Code world","start", " world").println(); getText("Hello Rosetta Code world","Hello", "end" ).println();</lang>
- Output:
Rosetta Code Hello Rosetta Code Rosetta Code world