version_compare

(PHP 4 >= 4.1.0, PHP 5, PHP 7, PHP 8)

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

Descrizione

version_compare(string $version1, string $version2, string $ operator = ?): int

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 8 notes

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18
eric at themepark dot com
18 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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9
mindplay.dk
10 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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10
insid0r at yahoo dot com
13 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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2
Bob Ray
6 years ago
Note that both leading and trailing spaces on your version numbers can break version_compare().

Tested on PHP 5.6.8:
<?php
echo  "\nShould be 0";
echo
"\n '1.0.0-pl' vs. '1.0.0-pl'  ---> " . version_compare('1.0.0-pl', '1.0.0-pl');
echo
"\n '1.0.0-pl' vs. ' 1.0.0-pl' ---> " . version_compare('1.0.0-pl', ' 1.0.0-pl');
echo
"\n ' 1.0.0-pl' vs. '1.0.0-pl' ---> " . version_compare(' 1.0.0-pl', '1.0.0-pl');
echo
"\n '1.0.0-pl' vs. '1.0.0-pl ' ---> " . version_compare('1.0.0-pl', '1.0.0-pl ');
echo
"\n '1.0.0-pl ' vs. '1.0.0-pl' ---> " . version_compare('1.0.0-pl ', '1.0.0-pl');

echo
"\n\nShould be 1";
echo
"\n '1.1.1-pl' vs. '1.0.0-pl'  ---> " . version_compare('1.1.1-pl', '1.0.0-pl');
echo
"\n ' 1.1.1-pl' vs. '1.0.0-pl' ---> " . version_compare(' 1.1.1-pl', '1.0.0-pl');

echo
"\n\nShould be -1";
echo
"\n '1.0.0-pl' vs. '1.1.1-pl'  ---> " . version_compare('1.0.0-pl', '1.1.1-pl');
echo
"\n '1.0.0-pl' vs. ' 1.1.1-pl' ---> " . version_compare('1.0.0-pl', ' 1.1.1-pl');

   
/* Output
Should be 0
'1.0.0-pl' vs. '1.0.0-pl'  ---> 0
'1.0.0-pl' vs. ' 1.0.0-pl' ---> 1
' 1.0.0-pl' vs. '1.0.0-pl' ---> -1
'1.0.0-pl' vs. '1.0.0-pl ' ---> 1
'1.0.0-pl ' vs. '1.0.0-pl' ---> -1

Should be 1
'1.1.1-pl' vs. '1.0.0-pl'  ---> 1
' 1.1.1-pl' vs. '1.0.0-pl' ---> -1

Should be -1
'1.0.0-pl' vs. '1.1.1-pl'  ---> -1
'1.0.0-pl' vs. ' 1.1.1-pl' ---> 1
    */
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2
rogier
10 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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3
opendb at iamvegan dot net
15 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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3
arnoud at procurios dot nl
18 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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0
sam at wyvern dot non-spammers-remove dot com dot au
18 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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