substr_compare

Description

int substr_compare ( string main_str, string str, int offset [, int length [, bool case_insensitivity]] )

substr_compare() compares main_str from position offset with str up to length characters.

Returns < 0 if main_str from position offset is less than str, > 0 if it is greater than str, and 0 if they are equal. If length is equal or greater than length of main_str and length is set, substr_compare() prints warning and returns FALSE.

If case_insensitivity is TRUE, comparison is case insensitive.

例子 1. A substr_compare() example
<?php echo substr_compare("abcde", "bc", 1, 2); // 0 echo substr_compare("abcde", "bcg", 1, 2); // 0 echo substr_compare("abcde", "BC", 1, 2, true); // 0 echo substr_compare("abcde", "bc", 1, 3); // 1 echo substr_compare("abcde", "cd", 1, 2); // -1 echo substr_compare("abcde", "abc", 5, 1); // warning ?>

add a note User Contributed Notes

sleek
23-May-2005 08:07


Modified version of the original posted function. Use this one:



<?php

if (!function_exists('substr_compare')) {

    function substr_compare($main_str, $str, $offset, $length = NULL, $case_insensitivity = false) {

        $offset = (int) $offset;



        // Throw a warning because the offset is invalid

        if ($offset >= strlen($main_str)) {

            trigger_error('The start position cannot exceed initial string length.', E_USER_WARNING);

            return false;

        }



        // We are comparing the first n-characters of each string, so let's use the PHP function to do it

        if ($offset == 0 && is_int($length) && $case_insensitivity === true) {

            return strncasecmp($main_str, $str, $length);

        }



        // Get the substring that we are comparing

        if (is_int($length)) {

            $main_substr = substr($main_str, $offset, $length);

            $str_substr = substr($str, 0, $length);

        } else {

            $main_substr = substr($main_str, $offset);

            $str_substr = $str;

        }



        // Return a case-insensitive comparison of the two strings

        if ($case_insensitivity === true) {

            return strcasecmp($main_substr, $str_substr);

        }



        // Return a case-sensitive comparison of the two strings

        return strcmp($main_substr, $str_substr);

    }

}

?>

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