[Wolfgang Lipp]
reminds me of dict.get()... i think in both cases being explicit::
beast = d.setdefault( 666, None ) beast = d.get( 666, None )
just reads better, allthemore since at least in my code what comes next is invariably a test 'if beast is None:...'. so
beast = d.setdefault( 666 ) if beast is None: ...
Do you actually do this with setdefault()? It's not at all the same as the get() example next, because d.setdefault(666) may _also_ have the side effect of permanently adding a 666->None mapping to d. d.get(...) never mutates d.
and
beast = d.get( 666 ) if beast is None: ...
a shorter but a tad too implicit for my feeling.
Nevertheless, 1-argument get() is used a lot. Outside the test suite, I've only found one use of 1-argument setdefault() so far, and it was a poor use (used two lines of code to emulate what dict.pop() does directly).