Regular Expression for decimal numbers

Question

I need a validation RegEx for decimal. It should allow up to 5 digits after decimal. Allow:

1    
1.0    
12.0    
12.01    
123.01    
1,123.01    
1,123.013
21,123.01234    
3,21,123.01234

How Can I do regex for this?

Do you want to allow the strings "1." or negative numbers? Also, "3,21,123.01234" seems really weird to be used - are you sure you want that to validate? — Andrei Krotkov, May 05 '10 at 18:43
@Andrei: it's valid in the Indian numbering system: http://en.wikipedia.org/wiki/Indian_numbering_system — Alan Moore, May 05 '10 at 23:18

score 4 · Answer 1 · answered May 05 '10 at 18:42

4

http://regexlib.com/Search.aspx?k=decimal

answered May 05 '10 at 18:42

Andrey

59,039
12
119
163

score 3 · Accepted Answer · answered May 05 '10 at 18:43

3

^[\d,]+(\.\d{1,5})?$

answered May 05 '10 at 18:43

Yuriy Faktorovich

67,283
14
105
142

@BipedalSharkYou're right, I am still confused about the use of the coma in general because of the test cases. – Yuriy Faktorovich May 05 '10 at 23:57

score 2 · Answer 3 · answered May 05 '10 at 23:43

Do you want to validate the positions of the commas? If so, this works for the Indian numbering system that you seem to be using:

^(?:\d{1,2},(?:\d{2},)*\d{3}|\d{1,3})(\.\d{1,5})?$

If you want to permit commas in the integer portion but don't care about their positions (except that it can't start or end with a comma), this will do:

^\d+(?:,\d+)*(\.\d{1,5})?$

score 0 · Answer 4 · answered May 05 '10 at 18:45

There an excellent library of commonly used regular expressions at http://regexlib.com/.

You an use a standard expression like: ^\$[0-9]+(\.[0-9][0-9])?$ or one of the alternative versions that do much the same thing, depending on the exact flavor you want to match.

Regular Expression for decimal numbers

4 Answers4

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