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Given strings

s1 = "abcfoodefbarghi"

and 

s2 = "abcbardefooghi"

How can I split s1 into "abc" and "defbarghi" and s2 into "abc" and "defooghi" That is: split a string into two on the first occurrence of either one of strings "foo" or "bar"

I suppose this could be done with s.split(/regexp/), but what should this regexp be?

Marek Miettinen
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  • Look at this question: [Split string once in javascript](http://stackoverflow.com/questions/2878703/split-string-once-in-javascript) – Jan Pfeifer Sep 23 '11 at 10:32

2 Answers2

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Use a Regular Expression in this way:

var match = s1.match(/^([\S\s]*?)(?:foo|bar)([\S\s]*)$/);
/* If foo or bar is found:
  match[1] contains the first part
  match[2] contains the second part */

Explanation of the RE:

  • [\S\s]*? matches just enough characters to match the next part of the RE, which is
  • (foo|bar) either "foo", or "bar"
  • [\S\s]* matches the remaining characters

Parentheses around a part of a RE creates a group, so that the grouped match can be referred, while (?:) creates a non-referrable group.

Rob W
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    This works and is well explained. In the end I needed to match the **last** occurrence and get the splitting string back, so I did `/^([\S\s]*)(foo|bar)([\S\s]*?)$/`. Thank you. – Marek Miettinen Sep 23 '11 at 12:19
2
str.replace(/foo|bar/,"\x034").split("\x034")

idea is replace the first occurrence with a special(invisible) String, and then split against this string.

Kent
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