how to match a number which is less than or equal to 100?

Question

I want to match a number which is less than or equal to 100, it can be anything within 0-100, but the regex should not match for a number which is greater than 100 like 120,

Answer 1

How about this for the regex:

^([0-9]|[1-9][0-9]|100)$

this would validate 7, 82, 100 for examples, but would not validate 07 or 082.

Check this out for more information (and variations including zero prefixing) on number range checking

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If you need to cater for floating point numbers you should read this, here is an expression you can use:

Floating point: ^[-+]?([0-9]|[1-9][0-9]|100)*\.?[0-9]+$