Change value of tuple based on data in other tuple

Question

I have two tuples

A=[(1,Poland),(2,Canada),(3,Germany)]
B=[(1,16),(2,20),(3,54)]

How can i merge them together based on the first value of a tuple to get something like this

C=[(Poland,16),(Canada,20),(Germany,54)]

I found This but this answer is from 2015 maybe you know better solution. My data will be at most 10/20 tuples so we aren't dealing with huge datasets

Are the couples of tuples always matching by index, or they can be shuffled? (Meaning that for example the `(1,16)` tuple in `B` will be second and not first) — Tomerikoo, Aug 16 '20 at 15:41
The first number in A is index of a Country that is second value, First number in B is the index of Country and the second one is how many order's were from this country — Marcel Czuryszkiewcz, Aug 16 '20 at 15:49
I understand that, but if the couples are always matching, why do you need the first number? The index of the list can be the indicator. So instead of a list of tuples you can just have a list of countries... — Tomerikoo, Aug 16 '20 at 15:51

Tomerikoo · Accepted Answer · 2020-08-16T16:04:51.703

If the tuples are always ordered as in the example, this is an easy case and you can simply use zip:

C = []
for a,b in zip(A, B):
    C.append(a[1], b[1])

#  or simply C = [(a[1], b[1]) for a,b in zip(A, B)]

If the order is not guaranteed (which makes the first number actually necessary), I would first convert one list to a dict, and then simply match the couples:

b_dict = dict(B)
C = []
for i, country in A:
    C.append((country, b_dict[i]))

#  or C = [(country, b_dict[i]) for i, country in A]

Of course this might require some handling of edge cases but I will leave that to you.

score 0 · Answer 2 · answered Aug 16 '20 at 15:44

0

This could be a solution.

[(x[1], y[1]) for y in B for x in A if x[0] == y[0]]

answered Aug 16 '20 at 15:44

mustafasencer

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score 0 · Answer 3 · answered Aug 16 '20 at 15:48

This look like a problem for pandas. You can turn them into pandas.Series() objects or pandas.DataFrame() and have the first number of the tuple as the index. Then just use the pandas.DataFrame.merge() to merge by index and you will have the three column dataframe or series.

Alternatively it would have to be a nested loop:

C = []
for i in A:
    for j in B:
        if i[0] == j[0]:
            C.append((i[1], j[1]))

Change value of tuple based on data in other tuple

3 Answers3