php regular expression-correction pattern

"Correction mode" is to specify a matching mode for the regular expression matching process, similar to the mode of mobile phones (family mode, conference mode, etc.):
Contains the following:
"Greedy matching" - means that when the matching results are ambiguous (multiple results appear), it will choose the result with the longest result;
"Lazy matching (U)" - means that when the matching result is ambiguous (multiple results appear), it will choose the result with the shortest result;
"i"——Ignore the upper and lower case of English letters in regular expressions;
"x" - ignore whitespace in regular expressions;
"s" - Let the metacharacter '.' match all characters including newlines;

If no correction mode is specified for the regular expression, the regular expression uses "greedy mode" by default;

The above introduces the PHP regular expression-correction mode, including the content. I hope it will be helpful to friends who are interested in PHP tutorials.