Regex pattern for numeric values

Question

I need an regular expression pattern to only accept positive whole numbers. It can also accept a single zero.

I do not want to accept decimals, negative number and numbers with leading zeros.

Any suggestions?

Answer 1

/([1-9][0-9]*)|0/

Answer 2

/^0|[1-9]\d*$/

Answer 3

"[1-9][0-9]*|0"

I'd just use "[0-9]+" to represent positive whole numbers.

Answer 4

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

Answer 5

My favorite: link text