In Python, the mere act of making a function call incurs a relatively large amount of overhead. If some function is called repeatedly in a tight loop, even if it isn’t a long-running function ...

The functions isEven and sum() are injected into the .filter() and .reduce() functions, respectively, to provide the behavior the functions require. Functional programming prefers recursion over loops ...

Recursive functions that use mutable data Ideally, you'd use the least expressive constructs that you can. Of course, if your language doesn't support tail call optimization, then that may also ...