Question

I want to implement the following validation. Match at least 5 digits and also some other characters between(for example letters and slashes). For example 12345, 1A/2345, B22226, 21113C are all valid combinations. But 1234, AA1234 are not. I know that {5,} gives minimum number of occurrences, but I don’t know how to cope with the other characters. I mean [0-9A-Z/]{5,} won’t work:(. I just don’t know where to put the other characters in the regex expression.

Thanks in advance!

Best regards,
Petar

Answer 1

Using the simplest regex features since you haven’t specified which engine you’re using, you can try:

    .*([0-9].*){5}
    |/|\   /|/| |
    | | \ / | | +--> exactly five occurrences of the group
    | |  |  | +----> end group
    | |  |  +------> zero or more of any character
    | |  +---------> any digit
    | +------------> begin group  
    +--------------> zero or more of any character

This gives you any number (including zero) of characters, followed by a group consisting of a single digit and any number of characters again. That group is repeated exactly five times.

That’ll match any string with five or more digits in it, along with anything else.

If you want to limit what the other characters can be, use something other than .. For example, alphas only would be:

[A-Za-z]*([0-9][A-Za-z]*){5}