Dostupnost ve verzích: `PHP 4.0`
Return information about characters used in a string
|Parametr||Datový typ||Výchozí hodnota||Poznámka|
||není||The examined string.|
||null||See return values.|
Depending on mode count_chars returns one of the following: 0 - an array with the byte-value as key and the frequency of every byte as value. 1 - same as 0 but only byte-values with a frequency greater than zero are listed. 2 - same as 0 but only byte-values with a frequency equal to zero are listed. 3 - a string containing all unique characters is returned. 4 - a string containing all not used characters is returned.