Some usages of PHP trim() function, usage of phptrim function_PHP tutorial

Some usages of PHP trim() function, usage of phptrim function

　 string trim ( string $str [, string $charlist ] ) - Remove whitespace characters (or other characters) at the beginning and end of the string

The trim() function removes spaces, tabs, line feeds, carriage returns, and vertical characters by default when the second parameter is empty. Tab characters, etc., when adding the second parameter

1) trim(' "string"', '"sg'); // Final output: "strin

2) trim(' "string" ', '"sg'); // Final output: "string"

2)trim('"string"', '"sg'); // Final output: trin

　So the trim() function first removes the blank characters at the beginning and end of the characters, and then filters out the given characters (list) to be removed. , also applies to ltrim(), rtrim() functions