regular expression for valid 2 digit decimal number

Question

I want to have a validation in php for price which can be 100 or 100.45 The 2 decimal places will be optional.

Now the validation should allow only digits.

So far i managed to achieve it

if (!preg_match('/^[0-9]+(\.[0-9]{1,2})?/', "100")) { echo "Invalid"; } else { echo "Valid"; }

but the issue here is that it is showing valid even if i enter 100a.00 or 100a or 100.a00

Please help me in fixing it so that only digits are allowed i.e 100 or 100.00 format

Have you tried adding a $ at the end, to match the end of the string? At the moment, it's matching a valid sequence of characters at the start with ^, so 100a is valid - the a is ignored, because the 100 is valid. — andrewsi
– andrewsi, Commented May 16, 2013 at 13:00

Bart Friederichs · Accepted Answer · 2013-05-16 12:59:24Z

21

Try this:

if (!preg_match('/^[0-9]+(\.[0-9]{1,2})?$/', "100"))

answered May 16, 2013 at 12:59

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1 Comment

what if the number length is more than 2.

ChristopheBrun · Accepted Answer · 2013-05-16 13:00:14Z

Lacks a $ in your regex. Presently, the first 3 characters in '100a...' match your regex.

preg_match('/^[0-9]+(\.[0-9]{1,2})?$/', "100")

should do the trick.