ctype_alpha

(PHP 4 >= 4.0.4, PHP 5, PHP 7)

Check for alphabetic character(s)

bool ctype_alpha ( string $text )

Checks if all of the characters in the provided string, text, are alphabetic. In the standard C locale letters are just [A-Za-z] and ctype_alpha() is equivalent to (ctype_upper($text) || ctype_lower($text)) if $text is just a single character, but other languages have letters that are considered neither upper nor lower case.

Parameters:

text

The tested string.

Returns:

Returns TRUE if every character in text is a letter from the current locale, FALSE otherwise.

Notes:

If an integer 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.

Examples:

A ctype_alpha() example (using the default locale)

<?php
$strings = array('KjgWZC', 'arf12');
foreach ($strings as $testcase) {
    if (ctype_alpha($testcase)) {
        echo "The string $testcase consists of all letters.\n";
    } else {
        echo "The string $testcase does not consist of all letters.\n";
    }
}
?>

The above example will output:

The string KjgWZC consists of all letters.
The string arf12 does not consist of all letters.