PHP5中文手册·Compares two "PHP-standardized" version number strings -- 追寻梦想＞编程乐园＞PHP 编程

说明

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.

参数

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.

返回值

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.

范例

Example#1 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");
?>

注释

Note: The PHP_VERSION constant holds current PHP version.


	PHP5中文手册 sys_get_temp_dir zend_logo_guid PHP Options/Info PHP Manual version_compare (PHP 4 >= 4.0.7, PHP 5) version_compare — Compares two "PHP-standardized" version number strings 说明 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. 参数 `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. 返回值 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. 范例 Example#1 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"); ?>` 注释 Note: The `PHP_VERSION` constant holds current PHP version. sys_get_temp_dir zend_logo_guid PHP Options/Info PHP Manual