Storing Python dictionary entries in the order they are pushed
Implementations of order-preserving dictionaries certainly do exist.
There is this one in Django, confusingly called SortedDict
, that will work in Python >= 2.3 iirc.
Try python 2.7 and above, probably 3.1, there is OrderedDict
http://www.python.org/
http://python.org/download/releases/2.7/
>>> from collections import OrderedDict
>>> d = OrderedDict([('first', 1), ('second', 2),
... ('third', 3)])
>>> d.items()
[('first', 1), ('second', 2), ('third', 3)]
PEP 372: Adding an ordered dictionary to collections
Use a list to hold the key order
Dictionaries in Python are implemented as hash tables, which is why the order appears random. You could implement your own variation of a dict that sorts, but you'd lose out on the convenient syntax. Instead, keep track of the order of the keys, too.
Initialization:
keys = []
myDict = {}
While reading:
myDict[key] = value
keys.append(key)
While writing:
for key in keys:
print key, myDict[key]