ctype_lower()
ctype_lower() — Check for lowercase character(s).
Built-in function of PHP 8.5. The manual lists it as available in PHP 4 >= 4.0.4, PHP 5, PHP 7, PHP 8. This page is the reference card: signature, parameters and return value, plus the changelog and the example the manual provides.
What it does
Checks if all of the characters in the provided string, text, are lowercase letters.
Signature
ctype_lower(mixed $text): bool
Parameters
| Parameter | Type | What it takes |
|---|---|---|
| $text | mixed | The tested string. Note: If an int between -128 and 255 inclusive is provided, it is interpreted as the ASCII value of a single character (negative values have 256 added in order to allow characters in the Extended ASCII range). Any other integer is interpreted as a string containing the decimal digits of the integer. Warning As of PHP 8.1.0, passing a non-string argument is deprecated. In the future, the argument ... |
Return value
Returns true if every character in text is a lowercase letter in the current locale. When called with an empty string the result will always be false.
Example
A runnable snippet:
$strings = array('aac123', 'qiutoas', 'QASsdks'); foreach ($strings as $testcase) { if (ctype_lower($testcase)) { echo "The string $testcase consists of all lowercase letters.\n"; } else { echo "The string $testcase does not consist of all lowercase letters.\n"; } }
Output:
The string aac123 does not consist of all lowercase letters. The string qiutoas consists of all lowercase letters. The string QASsdks does not consist of all lowercase letters.
See also
ctype_alpha(), ctype_upper(), setlocale()
All PHP 8.5 built-in functions
Reference card built from the PHP manual page ctype_lower() (PHP documentation, CC BY 3.0). The page is generated from the manual, so the wording of the parameter and return value text follows php.net.