Regular Expression Pattern With A Variable

Question

I am using regular expression to check number of digits after decimal.

This is working fine when it is used for two or three digits, for example \d{2} or \d{3}, but what if I need to pass a variable instead of 2 and 3?

How do I pass a variable to the pattern? Is it possible?

could you please show me how to do that ,,,, how do i build that — Priyank Patel
– Priyank Patel, Commented Mar 1, 2012 at 9:17

Sudhir Bastakoti · Accepted Answer · 2012-03-01 09:17:25Z

3

You can use RegExp, like;


//just an example though
var i = 2;
var pattern = new RegExp("\\d{"+i+"}$");

answered Mar 1, 2012 at 9:17

Sudhir Bastakoti

100k15 gold badges163 silver badges169 bronze badges

Sign up to request clarification or add additional context in comments.

2 Comments

Rob W Over a year ago

Double backslash instead of one.

Priyank Patel Over a year ago

This worked for me var no=2; var rxDatePattern = new RegExp("^(?:\\d*\\.\\d{" + no + "})$");

Odinn · Accepted Answer · 2012-03-01 09:17:12Z

1

You can write a function that generates the RegEx string with the parameter you provide for the number or decimal digits you need.

answered Mar 1, 2012 at 9:17

Odinn

8085 silver badges23 bronze badges

3 Comments

Priyank Patel Over a year ago

could you help me out with an example ,,,, as m relatively new to regular expressions

Odinn Over a year ago

function getRegEx(int len) { return "\d{" + len + "}"; } and then you generate the RegEx with: reg_ex = getRexEx(6) to generate a RegEx to check for 6 decimal digits. You can't put variable in RegEx you need to create a string for them.

Priyank Patel Over a year ago

Thanks Odinn ,,, i understood your example..It helped me a lot..Thanks

ZZ-bb · Accepted Answer · 2012-03-01 09:18:48Z

0

What about just defining the range of the digits: \d{2,3}?

answered Mar 1, 2012 at 9:18

ZZ-bb

2,1651 gold badge24 silver badges33 bronze badges

1 Comment

Jean Dok Over a year ago

Something like this should work : var i=2, j=3, regex = new RegExp("^\\d{"+ i +","+ j +"}$", "g");

giorashc · Accepted Answer · 2012-03-01 09:22:14Z

0

This might be useful : 10+ Useful JavaScript Regular Expression Functions to improve your web applications efficiency

answered Mar 1, 2012 at 9:22

giorashc

13.7k3 gold badges38 silver badges76 bronze badges

Collectives™ on Stack Overflow

Regular Expression Pattern With A Variable

4 Answers 4

2 Comments

3 Comments

1 Comment

Comments

Linked

Hot Network Questions

Collectives™ on Stack Overflow

4 Answers 4

2 Comments

3 Comments

1 Comment

Comments

Linked

Related