Why trim() function is used in php? code example

Example 1: trim function php

/* Removes whitespace from beginning and end of a string if
* the second parameter is omitted
* First parameter must be the string
* Second parameter is optional and can include an alternative character or set of characters.
*/

// Example 1
$string = " Hello world ";
$trimmedString = trim($string);
// Output = 'Hello world',

// Example 2
$string = "babcabcHello worldabbaca";
$trimmedString = trim($string, 'abc');
// Output = 'Hello world',

Example 2: trim | from right in php

$DATA=trim("abc|1|test|","|");