How can I modify this regular expression to allow numbers with just one point?

/[^0-9\.]/g

It currently allows:

• 0
• 0.13
• 0.13.1 (this should not be allowable)

How can I modify this regular expression to allow numbers with just one point?

/[^0-9\.]/g

It currently allows:

• 0
• 0.13
• 0.13.1 (this should not be allowable)

• javascript
• regex

• 1 There are so many similar questions linked on the right of this page. Didn't you see them when you were writing your question ? – Denys Séguret Commented Aug 9, 2013 at 14:35
• 1 You don't need to escape a dot in a character class – HamZa Commented Aug 9, 2013 at 14:36
• @dystroy, I did thorough search before posting, but none provided satisfiable answer. and none on the right point to what i am asking – Abhishek Madhani Commented Aug 9, 2013 at 14:38
• stackoverflow./questions/10169147/… – Denys Séguret Commented Aug 9, 2013 at 14:44
• Trying to find the duplicate, but this one is closed. Does it answer your question? Can you figure it out from the (pretty good) explanation there? – Ry- ♦ Commented Aug 9, 2013 at 14:46

6 Answers 6

Your regex doesn't matches what you say it matches. You have used negation in character class, and that too without any quantifier. Currently it would match any non-digit character other than ..

For your requirement, you can use this regex:

/^\d+(\.\d+)?$/

Make the match a positive one:

/^\d*(\.\d+)?$/

Any number of digits, optionally followed by a point and at least one digit. But it’s not worth it to keep a negative match.

If you want to disallow an empty string (which the original regular expression wouldn’t do), you could do this:

/^(?=.)\d*(\.\d+)?$/

But you could also just check for an empty string, which looks better anyways.

I guess this should do /^(\d*)\.{0,1}(\d){0,1}$/ OR /^(\d*)\.?(\d){0,1}$/

• (\d*) Represents number of digits before decimal.

• \. followed by {0,1} OR ? will make sure that there is only one dot.

• (\d){0,1} Allows only one digit after decimal.

You can try the following regex ^[-+]?\d*.?\d*$

Try,

(value.match(/^\d+([.]\d{0,1})?$/))

Try the following:

/^(\d*)(\.\d*)?$/g