PHP Manual
PHP Options/Info Functions
Compares two "PHP-standardized" version number strings

version_compare

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

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

Description

version_compare ( string $version1 , string $version2 ) : int

version_compare ( string $version1 , string $version2 , string $operator ) : bool

version_compare() compares two "PHP-standardized" version number strings.

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 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 the third optional operator argument is specified, test for a particular relationship. The possible operators are: <, lt, <=, le, >, gt, >=, ge, ==, =, eq, !=, <>, ne respectively.

This parameter is case-sensitive, 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. If an unsupported operator is given, NULL is returned.

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

<?phpif (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";}?>

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().

Php/docs/function.version-compare

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