PHP: How to check if a string starts with a specified string?

Question

I'm trying to check if a string starts with http. How can I do this check?

$string1 = 'google.com';
$string2 = 'http://www.google.com';

Answer 1

Use strpos():

if (0 === strpos($string2, 'http')) {
   // It starts with 'http'
}

Remember the three equals signs (===). It will not work properly if you only use two. This is because strpos() will return false if the needle cannot be found in the haystack.

Answer 2

substr( $string_n, 0, 4 ) === "http"

If you're trying to make sure it's not another protocol. I'd use http:// instead, since https would also match, and other things such as http-protocol.com.

substr( $string_n, 0, 7 ) === "http://"

Answer 3

Also work:

if (eregi("^http:", $url)) {
 echo "OK";
}

Answer 4

there is also the strncmp() function and strncasecmp() function, perfect for this situation.