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Jorge Ponti
Asked: 2020-07-21 13:18:32 +0800 CST 2020-07-21 13:18:32 +0800 CST

Compare 2 dictionaries in python to create another dictionary with matching keys

  • 772

I am programming a development and I want to compare 2 dictionaries, which in common have keys of the same name.

For example dictionary 1 is of the form:

    dic1 = {'0': [2.4636363650000002], '6': [4.1666666650000002], '9': [4.8333333349999998], '11': [3.5000000090000012], '14': [6.6181818249999989]}

Dictionary 2 is of the form:

    dic2 = {'0': [2, 3, 4], '6': [5,6,7], '19': [4.8333333349999998], '10': [4.8333333349999998], '12': [3.5012]}

Seeing, dictionary 2 matches the 1 keys '0' and '6'.

My idea is to create a dictionary 3 containing only this:

    dic3 = {'0': [2, 3, 4], '6': [5,6,7]}

What I am doing is creating lists with the keys of each dictionary, then I compare these lists and in the new dictionary I add those elements of the keys that match. I want to know if you know of a faster and more efficient way than looping through and creating lists, since there are so many keys I have.

python

3 Answers

  1. Best Answer

    There is a very simple method using "dictionary compressions" :

    dic3 = {k:v for (k,v) in dic2.items() if k in dic1}
    • 6 
  2. dic3 = set(dic1).intersection(set(dic2))
    • 3

  3. With a for loop you can get the key of each item in the dictionary and iterate through it.

    for i in dic1:
   print i
   print dic1[i]
    • 0