range() returns an array of
elements from low to high, inclusive. If low
high, the sequence will be from high to low.
New parameter: The optional step parameter was added in 5.0.0.
If a step value is
given, it will be used as the increment between elements in
the sequence. step should
be given as a positive number. If not specified, step will default to 1.
注: Prior to version 4.1.0 the range() function only generated incrementing integer arrays. Support for character sequences and decrementing arrays was added in 4.1.0.