Returns the number of elements in var, which is typically an array (since anything else will have one element).
If var is not an array, 1 will be returned (exception: count(NULL) equals 0).
count() may return 0 for a variable that isn't set, but it may also return 0 for a variable that has been initialized with an empty array. Use isset() to test if a variable is set.
Please see the Arrays section of the manual for a detailed explanation of how arrays are implemented and used in PHP.
Note: The sizeof() function is an alias for count().