Fixed-length variables are stored in a contiguous block of memory, making access and manipulation faster. Variable-length variables, on the other hand, require additional overhead to manage dynamic memory allocation, which can slow down operations, particularly in real-time systems.

Example:

1import array
2
3fixed_array = array.array('i', [1, 2, 3, 4, 5])
4
5dynamic_list = [1, 2, 3, 4, 5]

Here, array.array provides a fixed-length array, offering more predictable performance than dynamic lists.

References