Simple way to use variables in regex

Question

This almost has the answer... How do you use a variable in a regular expression?

I need to know if I can use variables instead of hardcode in the regex?

str1 = str1.replace(/abcdef/g, "stuvwxyz");

can I use variables instead of /abcdef/g and "stuvwxyz"

Darin Dimitrov · Accepted Answer · 2011-06-20 22:18:58Z

7

Of course that you can, every single bit of this can be dynamic:

var pattern = 'abcdef';
var input = 'stuvwxyz';
var modifiers = 'g';
var regex = new RegExp(pattern, modifiers);
var str1 = 'Hello abcdef';
str1 = str1.replace(regex, input);

Checkout the docs as well.

edited Jun 20, 2011 at 22:18

answered Jun 20, 2011 at 22:13

Darin Dimitrov

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5 Comments

kennebec Over a year ago

Is there any reason to use new here?

Darin Dimitrov Over a year ago

@kennebec, you may checkout the following thread about the new keyword in javascript: stackoverflow.com/questions/383402/…

gravityboy Over a year ago

These answers are all just about the same (or were, you did some fast editing) but you were first.

Ruan Mendes Over a year ago

Other answers don't mention how to make the regex dynamic, just the string to be searched and the what to replace it with.

gravityboy Over a year ago

@juan-mendes yes juan... that is why I said "or were" he edited really fast... he is good. His initial answer was just like the rest.

FishBasketGordo · Accepted Answer · 2011-06-20 22:14:04Z

1

Yes.

var pattern = /abcdef/g;
var input = "stuvwxyz";
str1 = str1.replace(pattern, input);

answered Jun 20, 2011 at 22:14

FishBasketGordo

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Comments

TomHastjarjanto · Accepted Answer · 2011-06-20 22:15:24Z

1

Like this?

var regex = /abcdef/g;
var string = "stuvwxyz";
var str1 = "abcdef";
str1 = str1.replace(regex, string);

answered Jun 20, 2011 at 22:15

TomHastjarjanto

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