71 lines
1.8 KiB
Plaintext
71 lines
1.8 KiB
Plaintext
Operators ``++in++`` and ``++not in++``, also called https://docs.python.org/3/reference/expressions.html#membership-test-operations["membership test operators"], require that the right operand supports membership protocol.
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In order to support this membership protocol a user-defined class should implement at least one of the following methods: ``++__contains__++``, ``++__iter__++``, ``++__getitem__++``.
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This rule raises an issue when operators ``++in++`` and ``++not in++`` are called with a right operand not supporting membership protocol.
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== Noncompliant Code Example
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----
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myint = 42
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if 42 in myint: # Noncompliant. Integers don't support membership protocol
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pass
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class A:
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def __init__(self, values):
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self._values = values
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if "mystring" in A(["mystring"]): # Noncompliant. Class A doesn't support membership protocol
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pass
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----
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== Compliant Solution
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----
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mylist = [42]
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if 42 in mylist:
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pass
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class MyContains:
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def __init__(self, values):
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self._values = values
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def __contains__(self, value):
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return value in self._values
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if "mystring" in MyContains(["mystring"]): # Noncompliant. Class A don't support membership protocol
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pass
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# OR
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class MyIterable:
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def __init__(self, values):
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self._values = values
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def __iter__(self):
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return iter(self._values)
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if "mystring" in MyIterable(["mystring"]): # Noncompliant. Class A don't support membership protocol
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pass
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# OR
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class MyGetItem:
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def __init__(self, values):
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self._values = values
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def __getitem__(self, key):
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return self._values[key]
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if "mystring" in MyGetItem(["mystring"]): # Noncompliant. Class A don't support membership protocol
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pass
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----
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== See
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* https://docs.python.org/3/reference/expressions.html#membership-test-operations[Python documentation - Membership test operations]
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