Question

I am trying to validate a string of 3 numbers followed by / then 5 more numbers
I thought this would work

(/^([0-9]+[0-9]+[0-9]+/[0-9]+[0-9]+[0-9]+[0-9]+[0-9])/i)

but it doesn’t, any ideas what i’m doing wrong

Answer 1

First of all, you’re using / as the regexp delimiter, so you can’t use it in the pattern without escaping it with a backslash. Otherwise, PHP will think that you’re pattern ends at the / in the middle (you can see that even StackOverflow’s syntax highlighting thinks so).

Second, the + is “greedy”, and will match as many characters as it can, so the first [0-9]+ would match the first 3 numbers in one go, leaving nothing for the next two to match.

Third, there’s no need to use i, since you’re dealing with numbers which aren’t upper- or lowercase, so case-sensitivity is a moot point.

Try this instead

/^\d{3}\/\d{5}$/

The \d is shorthand for writing [0-9], and the {3} and {5} means repeat 3 or 5 times, respectively.

(This pattern is anchored to the start and the end of the string. Your pattern was only anchored to the beginning, and if that was on purpose, the remove the $ from my pattern)