Question

I’ve to create a regex with this rules:

1. Number are between 5-100
2. Number are separated by comma (55,70,90)
3. Number are unique in string

For example:

• 10,20,50 OK
• 10 ,20,50 NO (white space)
• 10,20,50, NO (final comma)
• 10,10,20 NO (unique)

Can you help me?

Answer 1

Although it may be possible to perform all checks with a regex, I think it’s not the right tool for the job.

I would:

• Use a regex to verify the string is only numbers and commas: ^(?:[0-9]+,)*[0-9]+$
• Use split(',', $input) to turn into array
• Loop over array and ensure numbers are between 5 – 100 (arithmetic comparison) and no duplicates (array comparison).