regex patterns - noob in PHP

Question

I have been testing and googling but still could'nt work out pattern to validate comma separated numbers.

9 digits long, numbers only, no spaces, leading number for each digit cannot be zero

Tried

^(?:\s*\d{9}\s*(?:,|$))+$

but no go

Note that commas are required since the input file should between 3 up to 20 (max) comma separated integers

Answer 1

preg_match('=^[1-9][0-9,]*$=', $x); should do it, unless you're saying the number must be 9 digits long (with optional commas? or are the commas required?), in which case try something like preg_match('=^[1-9][0-9]{2},?[0-9]{3},?[0-9]{3}$=', $x);

Answer 2

You mentioned that there should be no spaces, but you used \\s* (0+ whitespaces) in your pattern. Also, (?:,|$) matches a , or end of string, so your pattern allows a trailing , .

I suggest using

^[1-9]\d{8}(?:,[1-9]\d{8}){2,19}$

See the regex demo

Details :

• ^ - start of string
• [1-9] - the first digit of the 9-digit number cannot be zero, 1 to 9 only
• \\d{8} - the 8 remaining digits of the number
• (?:,[1-9]\\d{8}){2,19} - 2 to 19 (in total, 3 to 20) occurrences of
  • , - comma
  • [1-9]\\d{8}){2,19} - see above
• $ - end of string.