Javascript take part from string untill

Question

'Hello there everyone I'm Bob, I want to say something.'

Imagine me having this string, I'm wondering if there is a function which you can give to strings to search for in a string. The first string I is like the start, the second one should be the end. In example: I give the following strings to the function "Hello" and "I'". Then I want the function to return " there everyone " to me.

jQuery will do as well.

It's certainly possible to write such a function, but it doesn't exist natively. — Felix Kling, Dec 17 '13 at 07:07
but what if later you want returns `there everyone I'm Bob,` that between "Hello" and "I"? — Grundy, Dec 17 '13 at 07:21

score 2 · Answer 1 · edited May 23 '17 at 12:28

2

You can use .indexOf and .substring like so:

var first = str.indexOf("Hello");
var second = str.indexOf("I'm", first + from.length);
var result = str.substring(first + "Hello".length, second);

You can of course extract that into a function:

function between(str, from, to){
    var first = str.indexOf(from);
    var second = str.indexOf(to, first + from.length);
    return str.substring(first + from.length, second);
}
between(yourStr,"Hello","I'm");

Alternatively, you can extend String.prototype if that's your thing:

String.prototype.between = function(from, to){
    var first = this.indexOf(from);
    var second = this.indexOf(to, first + from.length);
    return this.substring(first + from.length, second);
}
// now this will work
str.between("Hello","I'm"); // " there everyone "

edited May 23 '17 at 12:28

Community

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answered Dec 17 '13 at 07:08

Benjamin Gruenbaum

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It's probably better to do `str.indexOf("I'm", first);`, to only look for the end token after the start token. – Felix Kling Dec 17 '13 at 07:09
1

@FelixKling nice catch, for the general case it is probably better - I'll edit it in. – Benjamin Gruenbaum Dec 17 '13 at 07:09
1

@FelixKling so i think `str.indexOf("I'm", first+"Hello".length);` is better if we search full word – Grundy Dec 17 '13 at 07:11

score 2 · Answer 2 · answered Dec 17 '13 at 07:11

2

var str = "Hello there everyone I'm Bob, I want to say something.";
var first = "Hello";
var second = "I";

var start = str.indexOf(first)+first.length;
var end = str.indexOf(second);

var subStr= str.slice(start , end);

console.log(subStr) // there everyone

answered Dec 17 '13 at 07:11

Sarath

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why you need `str.indexOf(second)-second.length` instead of `str.indexOf(second)`? – Grundy Dec 17 '13 at 07:15

score 0 · Accepted Answer · answered Dec 17 '13 at 07:18

0

You can use Regular Expression.

str = "Hello there everyone I'm Bob, I want to say something.";
result = str.match(/Hello(.*?)I/);
alert(result[1]);

*? for non-greedy match. http://jsfiddle.net/LV5t3/

answered Dec 17 '13 at 07:18

iForests

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Just wondering; what if my string was 'Hello, they're going to Ibiza, I ' not going.' - How can I get the part after "they'" until "' " ? I can't figure it out. – Anoniem Anoniem Dec 17 '13 at 07:27

Javascript take part from string untill

3 Answers3