PHP substr() function

substr(string_name, start_position, string_length_to_cut)

1. string_name: In this parameter, we pass the original string or the string that needs to cut or modified. This is a mandatory parameter
2. start_position: This refers to the position of the original string from where the part needs to be extracted. In this, we pass an integer. If the integer is positive it refers to the start of the position in the string from the beginning. If the integer is negative then it refers to the start of the position from the end of the string. This is also a mandatory parameter.
3. string_length_to_cut: This parameter is optional and of integer type. This refers to the length of the part of the string that needs to be cut from the original string. If the integer is positive, it refers to start from start_position and extract length from the beginning. If the integer is negative then it refers to start from start_position and extract length from the end of the string. If this parameter is not passed, then the substr() function will return the string starting from start_position till the end of string.

<?php

// PHP program to illustrate substr()
function Substring($str){
    $len = strlen($str);
    echo substr($str, 8), "\n";
    echo substr($str, 5, $len), "\n";
    echo substr($str, -5, 10), "\n";
    echo substr($str,-8, -5), "\n";
}

// Driver Code
$str="GeeksforGeeks";
Substring($str);

?>

Geeks
forGeeks
Geeks
for