Last updated: Sat, 24 Mar 2007

version_compare

(PHP 4 >= 4.0.7, PHP 5)

version_compare — Compares two "PHP-standardized" version number strings

Popis

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

version_compare() compares two "PHP-standardized" version number strings. This is useful if you would like to write programs working only on some versions of PHP.

The function first replaces _, - and + with a dot . in the version strings and also inserts dots . before and after any non number so that for example '4.3.2RC1' becomes '4.3.2.RC.1'. Then it splits the results like if you were using explode('.', $ver). Then it compares the parts starting from left to right. If a part contains special version strings these are handled in the following order: dev < alpha = a < beta = b < RC < pl. This way not only versions with different levels like '4.1' and '4.1.2' can be compared but also any PHP specific version containing development state.

Seznam parametrů

version1: First version number.
version2: Second version number.
operator: If you specify the third optional operator argument, you can test for a particular relationship. The possible operators are: <, lt, <=, le, >, gt, >=, ge, ==, =, eq, !=, <>, ne respectively. Using this argument, the function will return TRUE if the relationship is the one specified by the operator, FALSE otherwise.

Návratové hodnoty

version_compare() returns -1 if the first version is lower than the second, 0 if they are equal, and +1 if the second is lower.

Příklady

Příklad 1574. version_compare() example


<?php

// prints -1

echo version_compare("4.0.4", "4.0.6");



// these all print 1

echo version_compare("4.0.4", "4.0.6", "<");

echo version_compare("4.0.6", "4.0.6", "eq");

?>

Poznámky

Poznámka: The PHP_VERSION constant holds current PHP version.

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Last updated: Sat, 24 Mar 2007

add a note User Contributed Notes
version_compare

Hayley Watson
30-Jul-2007 10:31


Yes; I was incorrect. However "1.0pl" is greater than "1.0.1", since "pl" comes after any number (this should perhaps be noted in the documentation: dev < alpha = a < beta = b < RC < # < pl)

opendb at iamvegan dot net
11-Jun-2007 01:26


My concern at this point, is that Hayley Watson's comments may confuse some people - it did me, so I did some more investigation before replying...



According to all the unit tests (15) I have written using version_compare, I believe Hayley Watson is incorrect.  For example, all of these calls are true.



function testVersionBeta3ToBeta4()

{

    $this->assertTrue(opendb_version_compare('1.0b3', '1.0a4', '>'), '1.0b3 > 1.0a4');

}



function testVersionBeta6ToReleaseCandidate1()

{

    $this->assertTrue(opendb_version_compare('1.0RC1', '1.0b6', '>'), 'RC1 > 1.0b6');

}



So how is this any different (which does not return true)



function testVersion10pl1To101()

{

        $this->assertTrue(opendb_version_compare('1.0.1', '1.0pl1', '>'), '1.0.1 > 1.0pl1');

}



However when its changed to:



unction testVersion10pl1To101()

{

        $this->assertTrue(opendb_version_compare('1.0.1', '1.0pl1', '>'), '1.0.1 > 1.0.0pl1');

}



It works fine.  I do believe that the version_compare function works as follows:



$version1 $operator $version2

Hayley Watson
10-Jun-2007 06:47


To correct opendb at iamvegan dot net's misapprehension: "1.0pl1" is regarded as less than "1.0.1". But the call as you've written it asks whether "1.0pl1" is greater (">") than "1.0.1" - which it isn't.

opendb at iamvegan dot net
10-Jun-2007 05:01


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', '>')

MagicalTux at ookoo dot org
23-Oct-2006 06:38


To answer elmuerte's note (06-Jul-2006 03:24), you'd even better remove spaces than replacing them.



<?php

version_compare("1.0.0.0beta1", "1.0.0.0alpha2") == 1; // good

version_compare("1.0.0.0-beta 1", "1.0.0.0-alpha 2") == 1;

version_compare("1.0.0.0.beta 1", "1.0.0.0.alpha 2") == 1;

version_compare("1.0.0.0.beta.1", "1.0.0.0.alpha.2") == 1;

?>

arnoud at procurios dot nl
29-Sep-2004 02:28


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.

mina86 at tlen dot pl
30-Jun-2004 07:40


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().

aidan at php dot net
26-Jun-2004 03:02


This functionality is now implemented in the PEAR package PHP_Compat.



More information about using this function without upgrading your version of PHP can be found on the below link:



http://pear.php.net/package/PHP_Compat

eric at themepark dot com
21-Jun-2004 09:50


[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


}


?>

sam at wyvern dot non-spammers-remove dot com dot au
23-May-2004 11:18


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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