Regular expression one (PHP common regular expression matching function) ____ function

Note: $pattren Regular expression
$subject Matching Target data

Note: (1) Pre_match matches only once, and Pre_match_all matches all (2) The former is a one-dimensional array, while the latter is a two-dimensional array (3) function return value corresponding to the number of matches

Note: (1) both support array matching substitution, that is, $pattern, $replacement, $subject can preserve the array of all arrays (2) Replace, while filter retains only the substituted array

Note: Only match, do not replace preg_split (Pattern,array pattern, array input)
Explode () is a subset of the above letter amount
Note: Split Preg_quote ($STR)
To escape the regular operator in a string