CODEWITHSUNDEEP
pythonlisttuples
montonero
montonero

Reputation: 802

Merge items of two lists into list of tuples that also contains index

What would be the most pythonic way of achieving the following:

list_a = ["A", "B", "C"]
list_b = ["X", "Y", "Z"]

idx_start = 100

result = [ (100, "A", "X"), (101, "B", "Y"), (102, "C", "Z") ]

The lists are guaranteed to be of the same size.

Upvotes: 3

Views: 739

Answers (6)

Bad
Bad

Reputation: 5289

Since you accepted that your result can be a dictionary (or list) with tuples for values, try this:

>>> list_a = ['A', 'B', 'C']
>>> list_b = ['X', 'Y', 'Z']
>>> idx_start = 100
>>>
>>> result_list = list(enumerate(zip(list_a, list_b), start=idx_start))
>>> result_dict = dict(enumerate(zip(list_a, list_b), start=idx_start))
>>>
>>> print (result_list)
[(100, ('A', 'X')), (101, ('B', 'Y')), (102, ('C', 'Z'))]
>>> print (result_dict)
{100: ('A', 'X'), 101: ('B', 'Y'), 102: ('C', 'Z')}

Upvotes: 0

Malik Brahimi
Malik Brahimi

Reputation: 16711

Use a list comprehension:

[(i + start, a, b) for i, (a, b) in enumerate(zip(list_a, list_b))]

Upvotes: 1

Ade
Ade

Reputation: 33

I had the same issue using HashSet. What I did was instantiate a var inside a for loop adding index and both values inside the HashSet. Something logic like that:

for (int i=0; i<a.length(); i++) {
   result.add(i,list_a[i],list_b[i]);
}

Upvotes: 0

mkrieger1
mkrieger1

Reputation: 23144

from itertools import count
zip(count(idx_start), list_a, list_b)

Upvotes: 3

igavriil
igavriil

Reputation: 1021

Zip is also an option

zip(range(idx_start,idx_start+len(list_a)), list_a, list_b)

Upvotes: 2

Bhargav Rao
Bhargav Rao

Reputation: 52071

You can try a list comp

>>> list_a = ["A", "B", "C"]
>>> list_b = ["X", "Y", "Z"]
>>> idx_start = 100
>>> [(idx_start+i,list_a[i],list_b[i]) for i in range(len(list_a))]
[(100, 'A', 'X'), (101, 'B', 'Y'), (102, 'C', 'Z')]

Other ways include

  • [(idx_start+i,list_a[i],list_b[i]) for i,v in enumerate(list_a)]

Upvotes: 3

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