PHP : Strings - [1.2] Accessing Substrings

You want to extract part of a string, starting at a particular place in the string. For example, you want the first eight characters of a username entered into a form. 1.2.1 Solution Use substr( ) to select your substrings: $substring = substr($string,$start,$length); $username = substr($_REQUEST['username'],0,8); 1.2.2 Discussion If $start and $length are positive, substr( ) returns $length characters in the string, starting at $start. The first character in the string is at position 0: print substr('watch out for that tree',6,5); out f If you leave out $length, substr( ) returns the string from $start to the end of the original string: print substr('watch out for that tree',17); t tree If $start plus $length goes past the end of the string, substr( ) returns all of the string from $start forward: print substr('watch out for that tree',20,5); ree If $start is negative, substr( ) counts back from the end of the string to determine where your substring starts: print substr('watch out for that tree',-6); print substr('watch out for that tree',-17,5); t tree out f If $length is negative, substr( ) counts back from the end of the string to determine where your substring ends: print substr('watch out for that tree',15,-2); print substr('watch out for that tree',-4,-1); hat tr tre