runtimecompare approaches one problem · two ways
Compare Approaches
The same problem solved different ways in Python, run on the same input, with what really differs and when to use each.
Closure vs callable object
A counter that remembers how many times it was called.
what differs
The closure keeps count in an enclosing scope that only it can reach (nonlocal lets it rebind). The object stores it as an attribute anyone can read or change.
at a glance
| approach | use it when |
|---|---|
| A · closure | A small bit of state behind one function. |
| B · class with __call__ | The state should be inspectable (c.count), resettable, or there are several related operations. |
Watch out: Forgetting nonlocal makes count += 1 raise UnboundLocalError.
the outputs
Each approach runs on the same input.
concepts
closuresnonlocal__call__
learn it
functools.partial: fix some arguments now
related comparisons
Wrapper without wraps vs decorator with functools.wraps · def vs lambda