Usted buscó: lowercase (Coreano - Ruso)

filename to lowercase
На верхний

abcdefghijklmnopqrstuvwxyzall of the letters of the alphabet, lowercase
АБВГДЕЖЗИЙКЛМНОПРСТУФХЦЧШЩЪЫЬЭЮЯall of the letters of the alphabet, lowercase

xheight - the height in pixels of a lowercase x.
Уровень выше

column names for queries on an oracle database are returned in lowercase.
След.

array_change_key_case() changes the keys in the input array to be all lowercase or uppercase. the change depends on the last optional case parameter. you can pass two constants there, case_upper and case_lower. the default is case_lower. the function will leave number indices as is.
Пример 1. Пример использования array_change_key_case()