The Substr () PHP Function is used to return part of a string. It is written as substr (string, start, optional length);.The string is whatever string you want to return a portion of. The start is how many characters in to skip before starting. Setting this to 3 would skip the first three and start returning at the forth character. Setting this to a negative number will start counting backwards from the end of the string.
Length is an optional parameter. If you set this to a positive number, it will return that number of characters. If you set this to a negative number it will count that many numbers from the end of the string and return whatever is left in the middle.

See how this works :

<?php
// this will return bcdefghijk
echo substr(‘abcdefghijk’, 1);
echo “<br>”;

// this will return defghijk
echo substr(‘abcdefghijk’, 3);
echo “<br>”;

// this will return abc
echo substr(‘abcdefghijk’, 0, 3);
echo “<br>”;

// this will return ijk
echo substr(‘abcdefghijk’, -3);
echo “<br>”;

// this will return bcdefghij
echo substr(‘abcdefghijk’, 1, -1);
echo “<br>”;

// this will return cdefgh
echo substr(‘abcdefghijk’, 2, -3);
echo “<br>”;
?>