CODEWITHSUNDEEP
pythonpython-3.xdictionarymath
Curious coder
Curious coder

Reputation: 11

Replacing dictionary values as a ratio of total values in the dict

My code example as below

 dict1 = {'c': 2, 'p': 1.0}

Want to alter values of the dict to represent a ratio of itself out of the total values 

dict1 = {'c': 0.6666666666666666, 'p': 0.3333333333333333}

Upvotes: 0

Views: 919

Answers (1)

zezollo
zezollo

Reputation: 5027

>>> d = {'c': 2, 'p': 1.0}                                                      
>>> d1 = { k: d[k]/sum(d[k] for k in d) for k in d }
>>> d1
{'c': 0.6666666666666666, 'p': 0.3333333333333333}
>>>

Note: avoid to use dict as variable name, it's a python's builtin.

Explanation of the one-liner:

  • d1 = {} -> d1 is a dictionary

  • d1 = { k: ... for k in d} -> all keys of d1 are the ones of d

  • sum(d[k] for k in d) -> calculate the sum of all values of d

So, the ... part above contains d[k]/sum(d[k] for k in d): this makes the quotient of the value matching the key k by the sum of all values of d.

EDIT: as alykhank suggested in comment, it's possible to do this in two lines and save execution time by not recomputing the sum at each iteration.

>>> total = sum(d.values())
>>> d2 = {k: d[k]/total for k in d}
>>> d2
{'c': 0.6666666666666666, 'p': 0.3333333333333333}
>>>

Upvotes: 1

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