Parse dictionary with Tuple as key

Question

My dictionary with tuple as a key is as follows:

Key represents the x and y coordinates. (x, y)

D1 = {(10,12): 23, (8,14): 45, (12, 9): 29}
D2 = {(2, 8) : 67, (12, 10): 23, (14, 8): 56}

Now, from the above Dictionary, I would like to perform the following

Sort dictionary D1 based on Keys
Sort dictionary D2 based on Keys
Simply, print the keys and values in D1
Simply, print the keys and values in D2
Then do the following:

(pseudocode)

total = 0
For each key (x, y) in D1,  
   if D2.has_key((y, x)):
      total = total + D1[(x, y)] * D2[(y, x)]
   Print total

What have you tried? How didn't it work? We can't help if you don't tell us what your problem was - all you have done is list what you would like to do. — Gareth Latty, May 27 '13 at 16:01
A dictionary can't be sorted. You can sort it into a list, though. Also, by which criteria do you want to sort the keys? — Tim Pietzcker, May 27 '13 at 16:03
I have tried for key1, val1 in D1: print key1, val1 It displays 8 14 12 9 10 12 — Kumar, May 27 '13 at 16:06
start from here: http://stackoverflow.com/questions/9001509/python-dictionary-sort-by-key — Ashwini Chaudhary, May 27 '13 at 16:17

score 1 · Accepted Answer · answered May 27 '13 at 16:26

(1/2) To sort a dict you have to use collections.OrderedDict (because normal dicts aren't sorted) Code:

from collections import OrderedDict
D1 = {(10,12): 23, (8,14): 45, (12, 9): 29}
D1_sorted = OrderedDict(sorted(D1.items()))

(3/4) Code: print(D1)

(5) convert your code to python

total = 0
for x, y in D1.keys():
    try:
        total = total + D1[(x, y)] * D2[(y, x)]
    except KeyError:
        pass
print total

score 0 · Answer 2 · answered May 27 '13 at 16:16

0

I think you're after (for your pseudo-code):

D1 = {(10,12): 23, (8,14): 45, (12, 9): 29}
D2 = {(2, 8) : 67, (12, 10): 23, (14, 8): 56}

total = sum(D1[k] * D2.get(k[::-1], 0) for k in D1.iterkeys())
# 3049

answered May 27 '13 at 16:16

Jon Clements

138,671
33
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Thanks everyone, able to get it. – Kumar May 27 '13 at 16:37

score 0 · Answer 3 · answered May 27 '13 at 20:22

>>> from collections import OrderedDict
>>> D1 = {(10,12): 23, (8,14): 45, (12, 9): 29}
>>> D2 = {(2, 8) : 67, (12, 10): 23, (14, 8): 56}
>>> D1 = OrderedDict(sorted(D1.items()))
>>> D2 = OrderedDict(sorted(D2.items()))
>>> print D1
OrderedDict([((8, 14), 45), ((10, 12), 23), ((12, 9), 29)])
>>> print D2
OrderedDict([((2, 8), 67), ((12, 10), 23), ((14, 8), 56)])
>>> sum(D1[(x, y)] * D2.get((y, x), 0) for x, y in D1)
3049

Parse dictionary with Tuple as key

3 Answers3