Regex to allow numbers and only one hyphen in the middle

php regex

Try this one:

/^\d{1,2}(-\d{1,2})?$/

One or two digits, followed by, optionally, ( a hyphen followed by one or two digits)

php regex

Fairly easy:

^\d+(-\d+)?$

At least one (+) digit (\d), followed by an optional group containing a hyphen-minus (-), followed by at least one digit again.

php regex

For strings containing only that pattern the following should work

^(\d{2}-)?\d{2}$

A group of 2 digits followed by minus ending with a group of 2 digits without minus.

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