updated from Atlas

03-dict-set/strkeydict.py

@@ -0,0 +1,74 @@
+"""StrKeyDict always converts non-string keys to `str`
+
+Test for initializer: keys are converted to `str`.
+
+    >>> d = StrKeyDict([(2, 'two'), ('4', 'four')])
+    >>> sorted(d.keys())
+    ['2', '4']
+
+Tests for item retrieval using `d[key]` notation::
+
+    >>> d['2']
+    'two'
+    >>> d[4]
+    'four'
+    >>> d[1]
+    Traceback (most recent call last):
+      ...
+    KeyError: '1'
+
+Tests for item retrieval using `d.get(key)` notation::
+
+    >>> d.get('2')
+    'two'
+    >>> d.get(4)
+    'four'
+    >>> d.get(1, 'N/A')
+    'N/A'
+
+Tests for the `in` operator::
+
+    >>> 2 in d
+    True
+    >>> 1 in d
+    False
+
+Test for item assignment using non-string key::
+
+    >>> d[0] = 'zero'
+    >>> d['0']
+    'zero'
+
+Tests for update using a `dict` or a sequence of pairs::
+
+    >>> d.update({6:'six', '8':'eight'})
+    >>> sorted(d.keys())
+    ['0', '2', '4', '6', '8']
+    >>> d.update([(10, 'ten'), ('12', 'twelve')])
+    >>> sorted(d.keys())
+    ['0', '10', '12', '2', '4', '6', '8']
+    >>> d.update([1, 3, 5])
+    Traceback (most recent call last):
+      ...
+    TypeError: 'int' object is not iterable
+
+"""
+# BEGIN STRKEYDICT
+
+import collections
+
+
+class StrKeyDict(collections.UserDict):  # <1>
+
+    def __missing__(self, key):  # <2>
+        if isinstance(key, str):
+            raise KeyError(key)
+        return self[str(key)]
+
+    def __contains__(self, key):
+        return str(key) in self.data  # <3>
+
+    def __setitem__(self, key, item):
+        self.data[str(key)] = item   # <4>
+
+# END STRKEYDICT