version_compare

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

version_compare — 对比两个「PHP 规范化」的版本数字字符串

说明

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

version_compare() 用于对比两个「PHP 规范化」的版本数字字符串。

此函数首先在版本字符串里用一个点 . 替换 _、- 和 +，也会在任意非数字前后插入一个点 .，这样，类似 '4.3.2RC1' 将会变成 '4.3.2.RC.1'。 接下来它会分割结果， 然后它会从左往右对比各个部分。 如果某部分包含了特定的版本字符串，将会用以下顺序处理： 列表中未找到的任意字符串 < dev < alpha = a < beta = b < RC = rc < # < pl = p。 这种方式不仅能够对比类似 '4.1' 和 '4.1.2' 那种不同的版本级别，同时也可以指定对比任何包含 PHP 开发状态的版本。

参数

version1

第一个版本数。

version2

第二个版本数。

operator

如果你指定了可选的第三个参数 operator，你可以测试两者的特定关系。 可以的操作符分别是：<、 lt、<=、 le、>、 gt、>=、 ge、==、 =、eq、 !=、<> 和 ne。

此参数区分大小写，它的值应该是小写的。

返回值

默认情况下，在第一个版本低于第二个时，version_compare() 返回 -1；如果两者相等，返回 0；第二个版本更低时则返回 1。

当使用了可选参数 operator 时，如果关系是操作符所指定的那个，函数将返回 true，否则返回 false。

范例

下例使用了 PHP_VERSION 常量，因为它执行的代码包含了 PHP 版本的值。

Example #1 version_compare() examples

<?php
if (version_compare(PHP_VERSION, '7.0.0') >= 0) {
    echo 'I am at least PHP version 7.0.0, my version: ' . PHP_VERSION . "\n";
}

if (version_compare(PHP_VERSION, '5.3.0') >= 0) {
    echo 'I am at least PHP version 5.3.0, my version: ' . PHP_VERSION . "\n";
}

if (version_compare(PHP_VERSION, '5.0.0', '>=')) {
    echo 'I am at least PHP version 5.0.0, my version: ' . PHP_VERSION . "\n";
}

if (version_compare(PHP_VERSION, '5.0.0', '<')) {
    echo 'I am still PHP 4, my version: ' . PHP_VERSION . "\n";
}
?>

注释

Note:

PHP_VERSION 常量包含了当前 PHP 的版本。

Note:

注意，类似 5.3.0-dev 的预发行版本，被认为是低于它们的最终发行版本（就像 5.3.0）。

Note:

指定类似 alpha、beta 的版本字符串是大小写敏感的。 版本字符串的来源若不遵循 PHP 标准，可能需要在调用 version_compare() 之前先用 strtolower() 转成小写。

参见

User Contributed Notes

Bob Ray 29-Oct-2015 11:07
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
    */
mindplay.dk 21-Jul-2012 03:10
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;
}

?>
rogier 30-Nov-2011 08:43
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
insid0r at yahoo dot com 06-Mar-2009 01:05
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;
}
?>
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', '>')
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.
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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