CODEWITHSUNDEEP
python
slopeofhope
slopeofhope

Reputation: 776

how do i make two new lists based on what the index is in a list?

So I think it is much easier to explain if I show an example: 

things = ["black", 7, "red', 10, "white", 15]

two new lists based on whether the index was even or odd. 

color = ["black", "red","white"]
size = [7,10,15]

Upvotes: 0

Views: 47

Answers (2)

TehTris
TehTris

Reputation: 3207

things = ["black", 7, "red", 10, "white", 15]
two_lists = zip(*[(x,things[things.index(x)+1]) for x in things[::2]])

>>> two_lists[0]
('black', 'red', 'white')
>>> two_lists[1]
(7, 10, 15)

the list manip part [(x,things[things.index(x)+1]) for x in things[::2]] seperates it into 3 list pairs ( almost like its ready for a dictionary or something... so cray cray)

the zip(* part, turns the whole array on its side

if you just did [(x,things[things.index(x)+1]) for x in things[::2]] withotu the zip part, then you could call dict() on it and return a dictionary, which might be more useful

>>> a = [(x,things[things.index(x)+1]) for x in things[::2]]
>>> a
[('black', 7), ('red', 10), ('white', 15)]
>>> cool_dict = dict(a)
>>> cool_dict['black']
7

Upvotes: 0

inspectorG4dget
inspectorG4dget

Reputation: 113915

In [4]: things = ["black", 7, "red", 10, "white", 15]

In [5]: color = things[::2]

In [6]: color
Out[6]: ['black', 'red', 'white']

In [7]: size = things[1::2]

In [8]: size
Out[8]: [7, 10, 15]

Upvotes: 8

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