75 lines
1.5 KiB
Python
75 lines
1.5 KiB
Python
"""StrKeyDict always converts non-string keys to `str`
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Test for initializer: keys are converted to `str`.
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>>> d = StrKeyDict([(2, 'two'), ('4', 'four')])
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>>> sorted(d.keys())
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['2', '4']
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Tests for item retrieval using `d[key]` notation::
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>>> d['2']
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'two'
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>>> d[4]
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'four'
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>>> d[1]
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Traceback (most recent call last):
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...
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KeyError: '1'
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Tests for item retrieval using `d.get(key)` notation::
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>>> d.get('2')
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'two'
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>>> d.get(4)
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'four'
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>>> d.get(1, 'N/A')
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'N/A'
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Tests for the `in` operator::
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>>> 2 in d
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True
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>>> 1 in d
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False
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Test for item assignment using non-string key::
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>>> d[0] = 'zero'
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>>> d['0']
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'zero'
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Tests for update using a `dict` or a sequence of pairs::
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>>> d.update({6:'six', '8':'eight'})
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>>> sorted(d.keys())
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['0', '2', '4', '6', '8']
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>>> d.update([(10, 'ten'), ('12', 'twelve')])
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>>> sorted(d.keys())
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['0', '10', '12', '2', '4', '6', '8']
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>>> d.update([1, 3, 5])
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Traceback (most recent call last):
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...
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TypeError: 'int' object is not iterable
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"""
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# tag::STRKEYDICT[]
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import collections
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class StrKeyDict(collections.UserDict): # <1>
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def __missing__(self, key): # <2>
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if isinstance(key, str):
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raise KeyError(key)
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return self[str(key)]
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def __contains__(self, key):
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return str(key) in self.data # <3>
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def __setitem__(self, key, item):
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self.data[str(key)] = item # <4>
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# end::STRKEYDICT[]
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