Regular expression to match floats only

Question

I need to do a regular expression to match the floats only, what i got is the following :

[\-\+]?[0-9]*(\.[0-9]+)?

But this match also the below 123123132 , 05/03/1994

I only need want to match the number with the decimal point

What do you mean with "floats only"? A decimal point is *required* for you? — L3viathan, May 07 '15 at 13:26
Don't escape `-` and `+` inside brackets (`-` is not a range because it's at the beginning, `+` doesn't need escaping). Change `*` to `+`. — lcd047, May 07 '15 at 13:33

L3viathan · Accepted Answer · 2015-05-07T14:02:00.397

3

Your regex is almost correct for your purpose.

It finds 123123132, because the last part is optional. Removing the ? solves that.

[-+]?[0-9]*(\.[0-9]+)

With that adjustment, it might still find matches in strings like .12/39/3239, if you don't want that to happen, insert enforce matching over the complete string by inserting ^ and $:

^[-+]?[0-9]*(\.[0-9]+)$

edited May 07 '15 at 14:02

answered May 07 '15 at 13:32

L3viathan

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score 1 · Answer 2 · edited May 07 '15 at 13:40

1

How about:

([+-]?[0-9]*\.[0-9]*)

You can see it working here

edited May 07 '15 at 13:40

karthik manchala

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answered May 07 '15 at 13:37

Matthew North

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score 1 · Answer 3 · answered May 07 '15 at 14:11

Here is a regexp handling also existing exponents:

[-+]?[0-9]*\.?[0-9]+([eE][-+]?[0-9]+)?

Regular expression visualization

Debuggex Demo

Additionally you should force the hole string to be matched to avoid matchings within your date values.

^[-+]?[0-9]*\.?[0-9]+([eE][-+]?[0-9]+)?$

By the way here is a nice tutorial about matching floating point numbers using regular expressions: http://www.regular-expressions.info/floatingpoint.html.

Regular expression to match floats only

3 Answers3