Original Translation
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if mydict.has_key(key): value = mydict[key] else: mydict[key] = getvalue(key) value = mydict[key]
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For this specific case, you could also use ``value = dict.setdefault(key, getvalue(key))``, but only if the ``getvalue()`` call is cheap enough because it is evaluated in all cases.
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Why isn't there a switch or case statement in Python?
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You can do this easily enough with a sequence of ``if... elif... elif... else``. There have been some proposals for switch statement syntax, but there is no consensus (yet) on whether and how to do range tests. See :pep:`275` for complete details and the current status.
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For cases where you need to choose from a very large number of possibilities, you can create a dictionary mapping case values to functions to call. For example::
Suggestion 0 by nobody:
Chaque fois que vous devez choisir parmi un très grand nombre de cas, vous pouvez créer un dictionnaire dont les valeurs sont des appels de fonctions. Par exemple::
Suggestion 1 by nobody:
Chaque fois que vous devez choisir parmi un très grand nombre de cas, vous pouvez créer un dictionnaire dont les valeurs sont des fonctions à appeler. Par exemple::
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def function_1(...): ... functions = {'a': function_1, 'b': function_2, 'c': self.method_1, ...} func = functions[value] func()
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For calling methods on objects, you can simplify yet further by using the :func:`getattr` built-in to retrieve methods with a particular name::
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def visit_a(self, ...): ... ... def dispatch(self, value): method_name = 'visit_' + str(value) method = getattr(self, method_name) method()
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It's suggested that you use a prefix for the method names, such as ``visit_`` in this example. Without such a prefix, if values are coming from an untrusted source, an attacker would be able to call any method on your object.
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Can't you emulate threads in the interpreter instead of relying on an OS-specific thread implementation?