Modifiers in PHP

The above uses a modifier u, see the description of the modifier.

The understanding of the PHP regular expression modifier:

Modifiers in a regular expression in PHP can change many of the regular features, making regular expressions more appropriate for your needs (note: Modifiers are sensitive to capitalization, which means "E" is not equal to "E").

The type and description of the PHP regular expression modifier:

I: If you add "I" to the modifier, the regular will remove the case sensitivity, i.e. "a" and "a" are the same.

M: Default regular start "^" and end "$" just for regular strings if you add "M" to the modifier, then the start and end will refer to each line of the string: the beginning of each line is "^" and the End is "$".

S: If "s" is added to the modifier, then the default "." Any character that represents anything other than a newline character will become any characters, including line breaks!

x: If the modifier is added, the white space character in the expression will be ignored unless it has been escaped.

E: This modifier is only useful for replacement, and represents the PHP code in replacement.

A: If you use this modifier, the expression must be the beginning of the matching string. For example, "/a/a" matches "ABCD".

E: In contrast to "M", if this modifier is used, then "$" will match the end of the absolute string, not the line break, which is turned on by default.

U: Similar to question mark, used to set "greedy mode".

Modifiers in PHP