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The content of this article is to share with you a summary of various judgments on strings in PHP. The content is very detailed and has certain reference value. I hope it can help friends in need.
1. Determine whether the string is empty
$namedRange !== NULL$pSheet === NULL
2. Determine whether the file exists and whether it is readable
(file_exists($pClassFilePath) === FALSE) || (is_readable($pClassFilePath) === FALSE)
3. Compare the two "PHP normalized" version number strings
version_compare ( string $version1 , string $version2 [, string $operator ] )
Return mixed string $version1 – version 1 required string $version2 – version 2 required string $operator – understood as Optional operators
are 7218c44422b12f1e5727956f42ed263a, gt, >=, ge, ==, =, eq, !=, a8093152e673feb7aba1828c43532094 and ne.
If the third parameter is specified, a boolean is returned. If the third parameter is not specified, the following three situations are returned:
The first version is lower than the second version. Return -1 when the first version is equal to the second version, return 0 when the first version is less than the second version, return 1**Example**version_compare(PHP_VERSION, '5.3.0') >= 0Recommended related articles:
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