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version_compare

(PHP 4 >= 4.1.0, PHP 5)

version_compare Confronta due stringhe contenenti il numero di versione di "PHP-standardized"

Descrizione

int version_compare ( string $version1 , string $version2 [, string $ operator ] )

version_compare() confronta due numeri di versione "PHP-standardized" . Questa funzione è utile quando si desideri che funzioni solo con alcune versioni di PHP.

La funzione version_compare() restituisce -1 se la prima verisone è minore della seconda, 0 se sono uguali, +1 se la sceonda è inferiore.

Per prima cosa la funzione sostituisce nella strina di versione le lettere _, - e + con un puntot . ed inserisce un punto . prima e dopo ogni carattere non numerico, in modo che, ad esempio, '4.3.2RC1' diventi ''4.3.2.RC.1'. Quindi divite il testo come se usasse explode('.', $ver). Poi confronta le parti cominciando da sinistra verso destra Se una parte contiene versioni speciali queste sono gestite nel seguente modo: dev < alpha = a < beta = b < RC < pl. In quest modo possono essere confrontati non solo differenti livelli di versioni quali '4.1' e '4.1.2', ma anche versioni di PHP in fase di sviluppo.

Specificando il terzo parametro opzionale operator si possono testare particolari relazioni. I possibili operatori sono: <, lt, <=, le, >, gt, >=, ge, ==, =, eq, !=, <>, ne. Utilizzando questi parametri, la funzione restituirà 1 se la relazione è una di quelle specificate dall'operatore, altrimenti 0.

Example #1 Esempio di uso di version_compare()

<?php
// prints -1
echo version_compare("4.0.4""4.0.6");

// queste stampano 1
echo version_compare("4.0.4""4.0.6""<");
echo 
version_compare("4.0.6""4.0.6""eq");
?>

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User Contributed Notes 10 notes

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9
eric at themepark dot com
10 years ago
[editors note]
snipbit fixed after comment from Matt Mullenweg

--jm
[/editors note]

so in a nutshell... I believe it works best like this:

<?php
if (version_compare(phpversion(), "4.3.0", ">=")) {
 
// you're on 4.3.0 or later
} else {
 
// you're not
}
?>
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3
opendb at iamvegan dot net
7 years ago
Something that may trip some folks up, but is useful to mention is that the following version comparison does not work quite as I expected:
    version_compare('1.0.1', '1.0pl1', '>')

However, its quite easy to get working:
    version_compare('1.0.1', '1.0.0pl1', '>')
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2
arnoud at procurios dot nl
9 years ago
If you're careful, this function actualy works quite nicely for comparing version numbers from programs other than PHP itself. I've used it to compare MySQL version numbers. The only issue is that version_compare doesn't recognize the 'gamma' addition that mysql uses as being later than 'alpha' or 'beta', because the latter two are treated specially. If you keep this in mind though, you should have no problems.
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2
loaded67 at hotmail dot com
4 years ago
This function is also usefull when working with multiple installations.

As php5.3+ will not have E_STRICT in the error_reporting anymore you can state:

<?php
ini_set
('error_reporting', (version_compare(PHP_VERSION, '5.3.0', '<') ? E_ALL|E_STRICT : E_ALL));
?>

Giving you all the error error reporting you want...
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1
rogier
2 years ago
Please note that supplying an operator that is not listed (e.g. ===), this function returns NULL instead of false.

Tested on PHP5.3.0, Win32
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1
sam at wyvern dot non-spammers-remove dot com dot au
10 years ago
Actually, it works to any degree:

<?php
version_compare
('1.2.3.4RC7.7', '1.2.3.4RC7.8')
version_compare('8.2.50.4', '8.2.52.6')
?>

will both give -1 (ie the left is lower than the right).
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0
insid0r at yahoo dot com
5 years ago
Since this function considers 1 < 1.0 < 1.0.0, others might find this function useful (which considers 1 == 1.0):

<?php
//Compare two sets of versions, where major/minor/etc. releases are separated by dots.
//Returns 0 if both are equal, 1 if A > B, and -1 if B < A.
function version_compare2($a, $b)
{
   
$a = explode(".", rtrim($a, ".0")); //Split version into pieces and remove trailing .0
   
$b = explode(".", rtrim($b, ".0")); //Split version into pieces and remove trailing .0
   
foreach ($a as $depth => $aVal)
    {
//Iterate over each piece of A
       
if (isset($b[$depth]))
        {
//If B matches A to this depth, compare the values
           
if ($aVal > $b[$depth]) return 1; //Return A > B
           
else if ($aVal < $b[$depth]) return -1; //Return B > A
            //An equal result is inconclusive at this point
       
}
        else
        {
//If B does not match A to this depth, then A comes after B in sort order
           
return 1; //so return A > B
       
}
    }
   
//At this point, we know that to the depth that A and B extend to, they are equivalent.
    //Either the loop ended because A is shorter than B, or both are equal.
   
return (count($a) < count($b)) ? -1 : 0;
}
?>
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0
Jonathon dot Reinhart at gmail dot com
6 years ago
I know this is somewhat incomplete, but it did a fair enough job for what I needed.  I was writing some code that needed done immediately on a server that was to be upgraded some time in the future.  Here is a quick replacement for version_compare (without the use of the operator argument). Feel free to add to this / complete it.

<?php
function version_compare2($version1, $version2)
{
   
$v1 = explode('.',$version1);
   
$v2 = explode('.',$version2);
   
    if (
$v1[0] > $v2[0])
       
$ret = 1;
    else if (
$v1[0] < $v2[0])
       
$ret = -1;
   
    else   
// Major ver are =
   
{
        if (
$v1[1] > $v2[1])
           
$ret = 1;
        else if (
$v1[1] < $v2[1])
           
$ret = -1;
       
        else 
// Minor ver are =
       
{
            if (
$v1[2] > $v2[2])
               
$ret = 1;
            else if (
$v1[2] < $v2[2])
               
$ret = -1;
            else
               
$ret = 0;
        }
    }
   
    return
$ret;
}
?>
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0
mina86 at tlen dot pl
10 years ago
Here's a wrapper which is more tolerant as far as order of arguments is considered:

<?php
function ver_cmp($arg1, $arg2 = null, $arg3 = null) {
  static
$phpversion = null;
  if (
$phpversion===null) $phpversion = phpversion();

  switch (
func_num_args()) {
  case
1: return version_compare($phpversion, $arg1);
  case
2:
    if (
preg_match('/^[lg][te]|[<>]=?|[!=]?=|eq|ne|<>$/i', $arg1))
      return
version_compare($phpversion, $arg2, $arg1);
    elseif (
preg_match('/^[lg][te]|[<>]=?|[!=]?=|eq|ne|<>$/i', $arg2))
      return
version_compare($phpversion, $arg1, $arg2);
    return
version_compare($arg1, $arg2);
  default:
   
$ver1 = $arg1;
    if (
preg_match('/^[lg][te]|[<>]=?|[!=]?=|eq|ne|<>$/i', $arg2))
      return
version_compare($arg1, $arg3, $arg2);
    return
version_compare($arg1, $arg2, $arg3);
  }
}
?>

It also uses phpversion() as a default version if only one string is present. It can make your code look nicer 'cuz you can now write:
<?php if (ver_cmp($version1, '>=', $version2)) something; ?>
and to check a version string against the PHP's version you might use:
<?php if (ver_cmp('>=', $version)) something; ?>
instead of using phpversion().
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-1
mindplay.dk
2 years ago
This little script can perhaps help you understand version comparison a little better - the output is displayed in the comment at the top. Tweak the list of versions if you need more examples...

<?php

#      1 lt 1.0
#    1.0 lt 1.01
#   1.01 eq 1.1
#    1.1 lt 1.10
#   1.10 gt 1.10b
#  1.10b lt 1.10.0

header('Content-type: text/plain');

$versions = array(
 
'1',
 
'1.0',
 
'1.01',
 
'1.1',
 
'1.10',
 
'1.10b',
 
'1.10.0',
);

$comps = array(
-
1 => 'lt',
 
0 => 'eq',
 
1 => 'gt'
);

foreach (
$versions as $version) {
  if (isset(
$last)) {
   
$comp = version_compare($last, $version);
    echo
str_pad($last,8,' ',STR_PAD_LEFT) . " {$comps[$comp]} {$version}\n";
  }
 
$last = $version;
}

?>
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