zip four lists to create dictionary with keys from two lists and values from another two lists-CodePudding

I have four lists:

list_a = ['hello', 'yes', 'you']
list_a_ind = [0, 1, 2]
list_b = ['he', 'here', 'great'] 
list_b_ind = [1, 2, 3]

I want to create a dictionary with combined index as keys and combined elements as values, result as below:

dictionary_ab = {(0,1): ('hello', 'he'), 
                 (1,2): ('yes', 'here'), 
                 (2,3): ('you', 'great)}

what's the fastest way to do it?

CodePudding user response：

This snippet will do the trick:

dict(zip(zip(list_a_ind, list_b_ind), zip(list_a, list_b)))

CodePudding user response：

You can use dict() directly with zip():

out = dict(zip(zip(list_a_ind, list_b_ind), zip(list_a, list_b)))
print(out)

Prints:

{(0, 1): ("hello", "he"), 
 (1, 2): ("yes", "here"), 
 (2, 3): ("you", "great")}

CodePudding user response：

The straightforward approach is a single zip unpacked and repacked via a dictcomp:

{(a, b): (c, d) for a, b, c, d in zip(list_a_ind, list_b_ind, list_a, list_b)}

For your short example inputs, this is the fastest solution (it has the lowest setup overhead), but the nested zip solution eventually wins out for large enough inputs (it has lower per-item overhead). This is a little easier to read to my mind, being a little more descriptive of what you're doing and how, but not enough to strongly prefer it (it's really fine either way).