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).
Note: The optional mode parameter is available as of PHP 4.2.0.
If the optional mode parameter is set to COUNT_RECURSIVE (or 1), count() will recursively count the array. This is particularly useful for counting all the elements of a multidimensional array. The default value for mode is 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.