如何检查两个字符串是否包含相同的字母？

Question

$textone = "pate"; //$_GET
$texttwo = "tape";
$texttre = "tapp";

if ($textone ??? $texttwo) {
echo "The two strings contain the same letters";
}
if ($textone ??? $texttre) {
echo "The two strings NOT contain the same letters";
}

What if statement am I looking for?

Answer 1

I suppose a solution could be to, considering the two following variables :

$textone = "pate";
$texttwo = "tape";

1. First, split the strings, to get two arrays of letters :

$arr1 = preg_split('//', $textone, -1, PREG_SPLIT_NO_EMPTY);
$arr2 = preg_split('//', $texttwo, -1, PREG_SPLIT_NO_EMPTY);

Note that, as pointed out by @Mike in his comment, instead of using preg_split() like I first did, for such a situation, one would be better off using str_split() :

$arr1 = str_split($textone);
$arr2 = str_split($texttwo);

2. Then, sort those array, so the letters are in alphabetical order :

sort($arr1);
sort($arr2);

3. After that, implode the arrays, to create words where all letters are in alphabetical order :

$text1Sorted = implode('', $arr1);
$text2Sorted = implode('', $arr2);

4. And, finally, compare those two words :

if ($text1Sorted == $text2Sorted) {
    echo "$text1Sorted == $text2Sorted";
}
else {
    echo "$text1Sorted != $text2Sorted";
}

---

Turning this idea into a comparison function would give you the following portion of code :

function compare($textone, $texttwo) {
    $arr1 = str_split($textone);
    $arr2 = str_split($texttwo);

    sort($arr1);
    sort($arr2);

    $text1Sorted = implode('', $arr1);
    $text2Sorted = implode('', $arr2);

    if ($text1Sorted == $text2Sorted) {
        echo "$text1Sorted == $text2Sorted<br />";
    }
    else {
        echo "$text1Sorted != $text2Sorted<br />";
    }
}

And calling that function on your two words :

compare("pate", "tape");
compare("pate", "tapp");

Would get you the following result :

aept == aept
aept != appt