Regex to find commas outside double quote in php

Question

What I have found so far is this

preg_match_all(\"/\'[^\']+\'|[^,]+/\", $input, $output);

Its supposed to find commas outside simple quotes, i

Answer 1

Not sure that your original pattern for single quotes is correct, this one will find all commas outside double quotes:

preg_match_all('~"(?:[^\\\"]+(?:\\\.)*|\\\.)*+"(*SKIP)(*F)|,~s', $subject, $matches);

pattern details:

~
"
(?:            # all possible content between quotes
    [^\\\"]+   # all that is not a double quote or a backslash
    (?:\\\.)*  # eventual escaped characters
  |            #  OR
    \\\.       # an escaped character
)*+            # repeat zero or more times (possessive)
"              # closing double quote, can be replaced with (?:"|\z) or "?
(*SKIP)(*F)    # forces the pattern to fail and to not retry double quoted parts
|              # OR
,              # a comma
~
s              # allow the dot to match newlines characters

Note: if you want to consider the substring after an orphan double quote as a quoted substring (until the end of the string), you can replace the closing double quote in the pattern with (?:"|\z) or more simply "?

Note2: to reduce drastically the number of steps needed to find a match, the pattern can be rewritten like this:

~[^,"]*+\K(?:"[^"\\\]*+(?:(?:\\\.)+[^\\\"]*)*+"?|,(*ACCEPT)|\z(*COMMIT).)(*SKIP)(*F)~s

or if you want to use the first character discrimination technic:

~(?=[",])(?:"[^"\\\]*+(?:(?:\\\.)+[^\\\"]*)*+"?(*SKIP)(*F)|,)~s