Javascript + Modify string

Question

What would be the quickest way to remove "everything" from a string, starting from the first "dot".

For example:

This.Is.A.Test

=> would become

This

For future benchmarking purposes, may I refer you to JS Perf? — David Thomas
– David Thomas, Commented May 20, 2012 at 20:32

Elliot Bonneville · Accepted Answer · 2012-05-20 20:38:29Z

4

You can use the the split() function like this:

"This.Is.A.Test".split(".")[0]; // will work even if there are no dots

Or you could use the substr() function in combination with the indexOf() function, like this:

var myStr = "This.Is.A.Test";
var justTheFirstBit = myStr.substr(0, myStr.indexOf(".")); // needs 1 dot minimum

edited May 20, 2012 at 20:38

answered May 20, 2012 at 20:29

Elliot Bonneville

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15 Comments

Kevin Ji Over a year ago

Fixed your substring function for you.

Elliot Bonneville Over a year ago

@mc10: substr is just as valid as substring. I'll be changing it back, although I appreciate the edit. :)

Derek 朕會功夫 Over a year ago

@ElliotBonneville - Too long, "This.Is.A.Test".replace(/\..+$/,""); is better.

Elliot Bonneville Over a year ago

@GGG: MDN says nothing about substr() being frowned upon.

Pencho Ilchev Over a year ago

second suggestion will not work if string contains no dots (indexOf returns -1). See my answer.

|

Kevin Ji · Accepted Answer · 2012-05-20 20:33:54Z

2

Alternatively,

var string = "This.Is.A.Test";
var newstring = string.substring(0, string.indexOf("."));

answered May 20, 2012 at 20:33

Kevin Ji

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1 Comment

Kevin Ji Over a year ago

@PenchoIlchev I'm assuming the OP's input text has a dot in it, based on his/her question. If necessary, you could always check if the dot existed or not.

Pencho Ilchev · Accepted Answer · 2012-05-20 20:34:42Z

0

This should have complexity of O(2n) and should ever search up to the first dot (twice).

var a = "This.Is.String";
var ind = a.indexOf(".");
ind = ind == -1 ? a.length : ind;
var b = a.substring(0, ind);

answered May 20, 2012 at 20:34

Pencho Ilchev

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Comments

Roko C. Buljan · Accepted Answer · 2012-05-20 20:37:15Z

0

$('#el').text( $('#el').text().split('.')[0] );

DEMO

https://developer.mozilla.org/en/JavaScript/Reference/Global_Objects/String/split

answered May 20, 2012 at 20:37

Roko C. Buljan

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Comments

Derek 朕會功夫 · Accepted Answer · 2012-05-20 20:42:32Z

0

　　　　　　　　　　　　 MDN - replace()

You can use the the replace() function like this:

"This.Is.A.Test".replace(/\..+$/,"");

This is the regular expression you need:

/\..+$/

edited May 20, 2012 at 20:42

answered May 20, 2012 at 20:33

Derek 朕會功夫

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