Compare two version strings in PHP

Question

How to compare two strings in version format? such that:

version_compare(\"2.5.1\",  \"2.5.2\") => -1 (smaller)
version_compare(\"2.5.2\",  \"2.5.2\") =&         


        

Answer 1

Also, you can use the PHP built-in function as below by passing an extra argument to the version_compare()

if(version_compare('2.5.2', '2.5.1', '>')) {
 print "First arg is greater than second arg";
}

Please see version_compare for further queries.

Answer 2

If your version compare doesnt work, the code below will produce your results.

function new_version_compare($s1,$s2){
    $sa1 = explode(".",$s1);
    $sa2 = explode(".",$s2);
    if(($sa2[2]-$sa1[2])<0)
        return 1;
    if(($sa2[2]-$sa1[2])==0)
        return 0;
    if(($sa2[2]-$sa1[2])>0)
        return -1;
}

Answer 3

From the PHP interactive prompt using the version_compare function, built in to PHP since 4.1:

php > print_r(version_compare("2.5.1",  "2.5.2")); // expect -1
-1
php > print_r(version_compare("2.5.2",  "2.5.2")); // expect 0
0
php > print_r(version_compare("2.5.5",  "2.5.2")); // expect 1
1
php > print_r(version_compare("2.5.11", "2.5.2")); // expect 1
1

It seems PHP already works as you expect. If you are encountering different behavior, perhaps you should specify this.

Answer 4

what you could do is parse each string, stop at the dot and add each number into a separate int.

so that your string 2.5.1 would become 3 integers:

$ver1 . "." . $ver2 . "." . $ver3

and your string 2.5.11 would become:

$ver1_2 . "." . $ver2_2 . "." . $ver3_2

then a bunch of if's to compare $ver1 with $ver1_2 and so on.

Answer 5

I have developed this function. I hope it helps. It can go to any length.

function updateAppVersion($appVersion1, $appVersion2)
{
    $releaseVersion = explode(".",$appVersion1);
    $deviceVersion = explode(".",$appVersion2);

    $len = count($deviceVersion);
    if(count($releaseVersion)>count($deviceVersion)){
        $len = count($releaseVersion);
    }

    for($i = 0;$i<$len;$i++){
        echo "[i=".$i."][r=".$releaseVersion[$i]."][d=".$deviceVersion[$i]."]";
        if(!isset($releaseVersion[$i])){
            return false;
        }
        else if(!isset($deviceVersion[$i])){
            return true;
        }
        else if($releaseVersion[$i]>$deviceVersion[$i]){
            return true;
        }
        else if($releaseVersion[$i]<$deviceVersion[$i]){
            return false;
        }

    }

    return false;
}