Question

I need a regular expression to describe a string that contains a minimum of three (3) and a maximum of six (6) of 2-digit numbers and 3-digit numbers in any order. The numbers should be separated by # but could also contain spaces. Examples of this string are:

34 #563# 23

123#678#12#44# 45

Answer 1

How about this:

^s*\d{2,3}\s*(?:#\s*\d{2,3}\s*){2,5}$

Explanation:

^         # Start of string
\s*       # optional whitespace
\d{2,3}   # match a number (2 to 3 digits)
\s*       # optional whitespace
(?:       # Match...
 \#       # - a hashmark
 \s*      # - optional whitespace
 \d{2,3}  # - a number
 \s*      # - optional whitespace
){2,5}    # 2 to 5 times
$         # End of string