CODEWITHSUNDEEP
pythonlist
Will W
Will W

Reputation: 1

printing corresponding item in list to another list containing numbers

My problem is this. These are the two lists

codes = ['a', 'b', 'c', 'a', 'e', 'f', 'g', 'a', 'i', 'j', 'a', 'l']
pas = [1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12]

How would I find the position of all the 'a' in the codes list. And then print out the corresponding item in the pas list. This is what the output should be. They should also be sorted with the .sort() function. 

1
4
8
11

I have come up with this code. (That doesnt work)

qwer = [i for i,x in enumerate(codes) if x == common]
qwe = [qwer[i:i+1] for i in range(0, len(qwer), 1)] 
print(pas[qwe])

What would be the best way to get the correct output?

Upvotes: 0

Views: 1002

Answers (4)

Pranjay Kaparuwan
Pranjay Kaparuwan

Reputation: 921

codes = ['a', 'b', 'c', 'a', 'e', 'f', 'g', 'a', 'i', 'j', 'a', 'l']
pas = [1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12]

[pas[index] for index, element in enumerate(codes) if element == "a"]

Upvotes: 0

Young
Young

Reputation: 254

Just added another way to use numpy:

import numpy as np
codes = np.array(['a', 'b', 'c', 'a', 'e', 'f', 'g', 'a', 'i', 'j', 'a', 'l'])
pas = np.array([1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12])

index = np.where(codes=='a')
values = pas[index]

In [122]: print(values)
[ 1  4  8 11]

Upvotes: 0

Ahasanul Haque
Ahasanul Haque

Reputation: 11164

>>> pas = [1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12]
>>> codes = ['a', 'b', 'c', 'a', 'e', 'f', 'g', 'a', 'i', 'j', 'a', 'l']
>>> result = sorted(i for i,j in zip(pas,codes) if j=='a')
>>> for i in result:
...     print i
... 
1
4
8
11

Upvotes: 4

Moinuddin Quadri
Moinuddin Quadri

Reputation: 48110

There are many ways to achieve it. Your example lists are:

>>> codes = ['a', 'b', 'c', 'a', 'e', 'f', 'g', 'a', 'i', 'j', 'a', 'l']
>>> pas = [1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12]

Approach 1: Using enumerate:

>>> indices = [pas[i] for i, x in enumerate(codes) if x == "a"]
indices = [1, 4, 8, 11]

Approach 2: Using zip:

>>> [p for p, c in zip(pas, codes) if c == 'a']
[1, 4, 8, 11]

Upvotes: 1

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