python.StackedDict.StackedDict Class Reference

Inheritance diagram for python.StackedDict.StackedDict:

Collaboration diagram for python.StackedDict.StackedDict:

Public Member Functions
	__init__ (self, *dicts)
	__getitem__ (self, k)
	__setitem__ (self, k, v)
	__len__ (self)
	__iter__ (self)
	has_key (self, k)
	copy (self)

Public Attributes
	dicts = dicts

Detailed Description

Allow lookups in multiple dictionaries while writing to one.

A StackedDict references a list of other dictionaries.
Reads try each dictionary in sequence, succeeding with the first dictionary
that contains the target key.  Modifications go to the last dictionary
in the list.

Notes: No attempt is made to deal with keys duplicated between dictionaries;
len() and __iter__ will process them all.  __delitem__ is not implemented.

Examples:
>>> from pprint import pprint
>>> d1 = {'a':'b'}
>>> d2 = {'c':'d'}
>>> d3 = {'e':'f'}
>>> d = StackedDict (d1, d2, d3)
>>> d['a']
'b'
>>> d['c']
'd'
>>> d['e']
'f'
>>> len(d)
3
>>> [x for x in d]
['a', 'c', 'e']
>>> 'c' in d
True
>>> 'c' in d
True
>>> 'd' in d
False
>>> d['c'] = 10
>>> d['c']
10
>>> d2
{'c': 10}
>>> d['x'] = 20
>>> d['x']
20
>>> pprint(d3)
{'e': 'f', 'x': 20}
>>> pprint(d.copy())
{'a': 'b', 'c': 10, 'e': 'f', 'x': 20}

Definition at line 14 of file StackedDict.py.

Constructor & Destructor Documentation

__init__()

python.StackedDict.StackedDict.__init__	(		self,
		*	dicts )

Definition at line 61 of file StackedDict.py.

    def __init__ (self, *dicts):
        self.dicts = dicts
        return
 
 

Member Function Documentation

__getitem__()

python.StackedDict.StackedDict.__getitem__	(		self,
			k )

Definition at line 66 of file StackedDict.py.

    def __getitem__ (self, k):
        for d in self.dicts:
            if k in d:
                return d[k]
        raise KeyError (k)
 
 

__iter__()

python.StackedDict.StackedDict.__iter__

(

self

)

Definition at line 86 of file StackedDict.py.

    def __iter__ (self):
        for d in self.dicts:
            for x in d: yield x
        return
 
 

__len__()

python.StackedDict.StackedDict.__len__

(

self

)

Definition at line 82 of file StackedDict.py.

    def __len__ (self):
        return sum([len(d) for d in self.dicts])
 
 

__setitem__()

python.StackedDict.StackedDict.__setitem__	(		self,
			k,
			v )

Definition at line 73 of file StackedDict.py.

    def __setitem__ (self, k, v):
        for d in self.dicts[:-1]:
            if k in d:
                d[k] = v
                return
        self.dicts[-1][k] = v
        return
 
 

copy()

python.StackedDict.StackedDict.copy

(

self

)

Definition at line 104 of file StackedDict.py.

    def copy (self):
        d = {}
        for i in range(len(self.dicts)-1, -1, -1):
            d.update(self.dicts[i])
        return d
        

has_key()

python.StackedDict.StackedDict.has_key	(		self,
			k )

Some code still uses this.
>>> d1 = {'a':'b'}
>>> d = StackedDict (d1)
>>> d.has_key ('a')
True
>>> d.has_key ('z')
False

Definition at line 92 of file StackedDict.py.

    def has_key (self, k):
        """Some code still uses this.
        >>> d1 = {'a':'b'}
        >>> d = StackedDict (d1)
        >>> d.has_key ('a')
        True
        >>> d.has_key ('z')
        False
        """
        return k in self
 
 

Member Data Documentation

dicts

python.StackedDict.StackedDict.dicts = dicts

Definition at line 62 of file StackedDict.py.

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The documentation for this class was generated from the following file:

• StackedDict.py