diff --git a/Doc/faq/programming.rst b/Doc/faq/programming.rst index 6cc1b52ed7b98b..81048c9422f321 100644 --- a/Doc/faq/programming.rst +++ b/Doc/faq/programming.rst @@ -518,14 +518,14 @@ desired effect in a number of ways. 1) By returning a tuple of the results:: - def func2(a, b): - a = 'new-value' # a and b are local names - b = b + 1 # assigned to new objects - return a, b # return new values - - x, y = 'old-value', 99 - x, y = func2(x, y) - print(x, y) # output: new-value 100 + >>> def func1(a, b): + ... a = 'new-value' # a and b are local names + ... b = b + 1 # assigned to new objects + ... return a, b # return new values + ... + >>> x, y = 'old-value', 99 + >>> func1(x, y) + ('new-value', 100) This is almost always the clearest solution. @@ -533,38 +533,41 @@ desired effect in a number of ways. 3) By passing a mutable (changeable in-place) object:: - def func1(a): - a[0] = 'new-value' # 'a' references a mutable list - a[1] = a[1] + 1 # changes a shared object - - args = ['old-value', 99] - func1(args) - print(args[0], args[1]) # output: new-value 100 + >>> def func2(a): + ... a[0] = 'new-value' # 'a' references a mutable list + ... a[1] = a[1] + 1 # changes a shared object + ... + >>> args = ['old-value', 99] + >>> func2(args) + >>> args + ['new-value', 100] 4) By passing in a dictionary that gets mutated:: - def func3(args): - args['a'] = 'new-value' # args is a mutable dictionary - args['b'] = args['b'] + 1 # change it in-place - - args = {'a': 'old-value', 'b': 99} - func3(args) - print(args['a'], args['b']) + >>> def func3(args): + ... args['a'] = 'new-value' # args is a mutable dictionary + ... args['b'] = args['b'] + 1 # change it in-place + ... + >>> args = {'a': 'old-value', 'b': 99} + >>> func3(args) + >>> args + {'a': 'new-value', 'b': 100} 5) Or bundle up values in a class instance:: - class callByRef: - def __init__(self, /, **args): - for key, value in args.items(): - setattr(self, key, value) - - def func4(args): - args.a = 'new-value' # args is a mutable callByRef - args.b = args.b + 1 # change object in-place - - args = callByRef(a='old-value', b=99) - func4(args) - print(args.a, args.b) + >>> class Namespace: + ... def __init__(self, /, **args): + ... for key, value in args.items(): + ... setattr(self, key, value) + ... + >>> def func4(args): + ... args.a = 'new-value' # args is a mutable Namespace + ... args.b = args.b + 1 # change object in-place + ... + >>> args = Namespace(a='old-value', b=99) + >>> func4(args) + >>> vars(args) + {'a': 'new-value', 'b': 100} There's almost never a good reason to get this complicated.