PHP Options/Info Functions
PHP Manual

version_compare

Compares two "PHP-standardized" version number strings

Description

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: any string not found in this list < dev < alpha = a < beta = b < RC = rc < # < pl = p. 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.

Parameters

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.

This parameter is case-sensitive, so values should be lowercase.

Return Values

By default, 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.

When using the optional operator argument, the function will return TRUE if the relationship is the one specified by the operator, FALSE otherwise.

Examples

The examples below use the PHP_VERSION constant, because it contains the value of the PHP version that is executing the code.

Example #1 version_compare examples

<?php
if (version_compare(PHP_VERSION, '6.0.0') >= 0) {
    echo 'I am at least PHP version 6.0.0, 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 using PHP 5, my version: ' . PHP_VERSION . "\n";
}

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

Notes

Note:

The PHP_VERSION constant holds current PHP version.

Note:

Note that pre-release versions, such as 5.3.0-dev, are considered lower than their final release counterparts (like 5.3.0).

Note:

Special version strings such as alpha and beta are case sensitive. Version strings from arbitrary sources that do not adhere to the PHP standard may need to be lowercased via strtolower before calling version_compare.

See Also

  • phpversion
  • php_uname
  • function_exists