phil phil - 1 year ago 54
Javascript Question

Regular Expression to get a string between two strings in Javascript

I have found very similar posts but I can't quite get my regular expression right here.

I am trying to write a regular expression which returns a string which is between two other strings. For example: I want to get the string which resides between the strings "cow" and "milk"

My cow always gives milk

would return

"always gives"

Here is the expression I have pieced together so far:


However this returns the string "cow always gives"


I was able to get what I needed using Martinho Fernandes' solution below. The exact code is:

var test = "My cow always gives milk";

var testRE = test.match("cow(.*)milk");

You'll notice that I am alerting the testRE variable as an array. This is because testRE is returning as an array, for some reason. The output from:

My cow always gives milk

Changes into:

always gives

Answer Source

A lookahead (that (?= part) does not consume any input. It is a zero-width assertion (as are boundary checks and lookbehinds).

You want a regular match here, to consume the cow portion. To capture the portion in between, you use a capturing group (just put the portion of pattern you want to capture inside parenthesis):


No lookaheads are needed at all.

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