Question

I am doing a quick duplicate check on a form. When comparing two strings, I was trying something like this:

if (stripos($_SESSION['website'], $f['website']))

I am getting this error:

Fatal error: Call to undefined function: stripos() in...

I do not want it to be an exact match, basically if the $_SESSION['website'] is http://www.google.com, I’d want stripos to return true if $f['website] is http://www.goog.com

Am I doing something wrong, or is there a better way to do this?

edit: I was doing some testing, and noticed if my $_SESSION['website'] variable contains www and .com. As does my $f['website] variable. shouldn’t strpos return that as true?

Answer 1

stripos(), as per the manual only exists in the core of PHP 5 or later. If stripos doesn’t exist, that would suggest you’re using PHP 4, which is wildly outdated. I suggest you upgrade. If for some insane reason you really can’t, you can always force the two strings to lowercase before calling strpos, which would have the same effect:

<?php
// PHP 5.
$pos = stripos( 'www.google.com', 'google.com' );

// PHP 4.
$pos = strpos( strtolower( 'www.google.com' ), strtolower( 'google.com' ) );

That said, there’s something more to your code: you’re checking if( stripos( $foo, $bar ) ) which would return 0 if the string $foo starts with the string $bar. You should check with if( stripos( $foo, $bar ) !== false ) instead.

On another note: I don’t think stripos will help you. You mentioned www.google.com and www.goog.com, which are two totally different things. The latter is not a substring of the former, and stripos checks for the starting position of a substring, it doesn’t do “loose comparison”.

If you want “like” and you have the terms in an array, you might want to check out the similar_text() function which will give you an indication of how similar two different strings are. As an example:

<?php
$similarity = 0;
similar_text( 'www.goog.com', 'www.google.com', $similarity );
var_dump( $similarity );

The above code would set $similarity to float(92.307692307692), which is the similarity of the two strings in percentages. You can decide the threshold for the similarity yourself, naturally.