str_pad(): String pad with specified length.strcmp(): Case sensitive string comparison.strcasecmp(): Case insensitive string comparison.function to collect part of a string with two landmarks.str_repeat: Repeating a string number of times.substr_count: Counting occurrence of sub string in main string.explode: Breaking a string to form array using delimiters.split: Breaking a string to form array using delimiters.

strrev: Reversing a string by using strrev function in PHP.

trim: Removing empty space from both sides of a string.

strlen: How to find length of a string in PHP?.

Marvellous.PHP Home Beginners guide Loops Date Form Array String Math Mail File - directory curl PHP & XML GD: graphs Calendar Filters PHP MySQL PDO MySQLi Session Scripts PDF Generation As we're starting five from the end and we are asking PHP not to copy the last four, we are in fact copying just one character, 'P', which, if you run the script, will be what $f ends up containing. With $e we specify a negative start and a positive length, with the end result being that PHP will start five characters from the end of the string ('P'), then copy four characters, meaning that $e will be set to 'Perl'.įinally, with $f, we have both a negative start value and a negative length, which translates as 'start five characters from the end of the string, and copy everything but the last four'. After running the code, $d will be set to 'Perl!', because PHP will start 5 characters from the end of the string, then copy from there till the end of the string. With $d, we start using a negative start value for parameter 2, -5. You already know how $a, b, and $c work - copy from character five till end, copy five characters from character five, and copy all but the last character respectively. That chunk of code demonstrates each possible way to use substr(). Here are some examples that should hopefully make things clear: You can even use a negative length with your negative start index. Using negative lengths allows you to say 'copy everything but the last three characters'.īut wait - there is even more! You can also use a negative start index, in which case you start copying start characters from the end. So, $b is set to 'ye, Perl', and $c is set to 'Goodbye'. However, $b and $c both use negative lengths, which mean that they take all the string except for length characters at the end. $a is quite straightforward, and copies five characters from index five onwards, giving 'ye, P'. For example, you can specify a negative number as parameter three for the length, and PHP will consider that number the amount of characters you wish to omit from the end of the string, as opposed to the number of characters you wish to copy. However, we're not finished - substr() can do more.

If you try it, you will see that it does just that - substr($string, 5, 4) returns the string 'ye, ', a four-letter word with a space making up the last character.įinally, with variable $f, we have 1 character being copied from index 10, which stores 'e' in $f. With 5 as parameter two and 4 as parameter 3, substr() should start from index five (the sixth character) and copy four characters. With $e we start using the third parameter. This line is in there to show you that even if you try to copy more than you have, PHP will not return an error - it will just return an empty string. With $d we start from index 50 (the 51st character) in the string 'Goodbye, Perl!', which clearly does not exist. $c has us copying from index 5 (the sixth character), and so $c will be set to 'ye, Perl!', as expected. With $b we get the expected behaviour, the entire string is copied, because we started at index 0. In PHP, strings an arrays start at 0 rather than 1, and, as we specified 1 as parameter two to substr(), it started copying from the second character and took all the letters to the end of the string. Here are some examples of basic usage:Īfter that code executes, $a will contain 'oodbye, Perl!' If you were expecting it to return the full string, do not worry - it is a common mistake. There is an optional third parameter to allow you to specify how many characters you want to read (the length you want to copy). The substr() function allows you to read just part of a string, and takes a minimum of two parameters - the string to work with, and where you want to start reading from. String substr ( string source, int start )

Php substring string