如何检查字符串是否以指定的字符串开头？ [重复]

Question

This question already has an answer here:

• startsWith() and endsWith() functions in PHP 31 answers

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';

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Answer 1

Use the substr function to return a part of a string.

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://"

And in general:

substr($string, 0, strlen($query)) === $query