compare two strings in php and show character differences

Question

Hi I am struggling to get this right:

I want to compare two strings and calculate their score in php.

What that means is I have two strings:

$string1="example1"; $string2="exumple22";

Now I want to compare the strings if they are equal - in this case they are not.

But additionally I want to see the characters that match. At least count them.

In this case that would be: 6;

I have tried this but I am stuck hers is my example:

enter code here
<?  
include("connect.php");
$query="SELECT * FROM data where ID = '1'";
$result = mysql_query($query) or die(mysql_error());


while($row = mysql_fetch_array($result))
{
    //echo "Score :{$row['scoreA']} <br>" ;
    $scoretemp=$row['scoreA'];
    $string1=$row['textA1'];
    $string2=$row['textA2'];


} 
mysql_close();

if (strcmp($string1, $string2) != 0){
    echo "not equal in a case-sensitive string comparison <br>";
$j = strlen($string1);
    for ($i = 0; $i < $j; $i++) {
    $stringtemp1++;
    echo $string1[$i].', ';
    echo $stringtemp1;
    }    

    $u = strlen($string2);
    for ($t = 0; $t < $u; $t++) {
    $stringtemp2++;
    echo $string2[$t].', ';
    echo $stringtemp2;
    }$scoreA=($stringtemp1 - $stringtemp2);    
    $stringtemp1=0;$stringtemp2=0;
}
else{
    echo "Stringmatch! <br>";
        $e = strlen($string1);
        for ($r = 0; $r < $e; $r++) {
        $stringtemp1++;
        echo $string1[$r].', ';
        echo $stringtemp1;
}$scoreA=$stringtemp1;
$stringtemp1=0;
}
 ?>

Solution 1

See http://www.php.net/manual/en/function.similar-text.php for how to use similar_text($str1, $str2)

This will give you the number of matching chars in both strings.

<?php
    echo similar_text("Hello World","Hello Peter");
?>

will give you 7 (the number of characters in common).

Solution 2

Try this

<?php

$string1 = 'example1';
$string2 = 'exumple22';

$matchingcharacters = [];
$mismatchingcharacters = [];

$len1 = strlen($string1);
$len2 = strlen($string2);

$similarity = $i = $j = $dissimilarity = 0;

while (($i < $len1) && isset($string2[$j])) {
    if ($string1[$i] == $string2[$j]) {
        $similarity++;
        $matchingcharacters[] = '['.$string1[$i].']';
    } else {
        $dissimilarity++;
        $mismatchingcharacters[] = '['.$string1[$i] . " & " . $string2[$j].']';
    }
    $i++;
    $j++;
}
echo 'First string : '.$string1.'<br>';
echo 'Second string : '.$string2.'<br>';
echo 'Similarity : ' . $similarity . '<br>';
echo 'Dissimilarity : ' . $dissimilarity . '<br>';
echo 'Matching characters : ' . implode(",", $matchingcharacters) . '<br>';
echo 'Mismatching characters : ' . implode(",", $mismatchingcharacters);

Solution 3

You can calculate the levenshtein distance between 2 strings:

In its simplest form the function will take only the two strings as parameter and will calculate just the number of insert, replace and delete operations needed to transform str1 into str2.