PHP preg_match - regular expression

Question

I have this text:

SU4R
C45G
G3HD
61U14XE7AR23 914K16W471LV V6SQ5V16LG91 24YL4HW956C3 UZ26J12K615V T741MH4N739W 31ST445G726H 621EH6VW7Q6M 55N629WJ945P 56TX2W6LC949 44DS765CF739 XC262HV1JZ6V 26YD4N1Y71F7 S4M3F1XeDC0D

I want to use preg_match to find specific type of code in that text, so I should contains:

• 4 or 12 characters
• it should returs all elements
• non case sensitive
• letters and numbers

I've ended with this:

preg_match("/^(?=.*\d)(?=.*[A-Za-z])[0-9A-Za-z!@#$%]{4,12}/", $input_line, $output_array);

But:

• it only works at http://www.phpliveregex.com/p/byZ
• it find only first 4 elements
• why when I try to use this page https://www.functions-online.com/preg_match.html it shows only 1 match?

Answer 1

Using preg_match_all(), something like this probably works
http://www.phpliveregex.com/p/bz0

 # '/(?<!\S)(?i:[a-z\d]{4}|[a-z\d]{12})(?!\S)/'

 (?<! \S )                     # whitespace boundary
 (?i:                          # case insensitive cluster group
      [a-z\d]{4}                    # 4 alnum
   |                              # or
      [a-z\d]{12}                   # 12 alnum
 )
 (?! \S )                      # whitespace boundary