字符串组合不再使用给定长度的字符串使用过的字母

Question

For example I have this string "qwertyuiopas" and the length to be returned is : 5

How can i make a function that would return all possible 5 character strings from the given text above?

example: qwert werty ewryt ... and so on

the letter should not be used again.

Answer 1

You could do this:

function getSubStrings($string, $subStringLength) {

    $subStrings = array();

    for ($i=0; $i < strlen($string) - $subStringLength; $i++) {
        $subStrings[] = substr($string, $i, $subStringLength);
    }

    return $subStrings;
}

// Testing

$string = "qwertyuiopas";
$length = 5;

var_dump(getSubStrings($string, $length));