From PHP manual:array array_change_key_case ( array $array [, int $case = CASE_LOWER ] )What does comma signify in a function definition?
What does comma signify in a function definition?
php;functions;definition
Comma is a separator between parameters in the parameter list.Comma is part of the parameter lists. Optional parameters are usually specified inside square brackets in documentation like so: [, int $case = CASE_LOWER]. Comma is added to specify that if you were to use the second optional parameter, you must have a comma separator as well.The fact that comma is inside square brackets, means it's only required when you have more than one parameter.  Another example with more optional parameters:array array_change_key_case ( array $array [, int $case = CASE_LOWER [, string $myValue = '' ]] )