array_walk, array_map situtaions
i want to know, in which situtaion array_walk and array_map are used, 

tell me, simply, what is array_map, what is array_walk, 


array_walk, array_map situtaions
===

i want to know, in which situtaion array_walk and array_map are used, 

tell me, simply, what is array_map, what is array_walk, 

