Creating Sublists from a “List”

Question

I have a list in a file, looks like this

c4a24534,2434b375,e750c718, .... 

I have split at \",\" and brought the below list.

x         


        

Answer 1

Assuming this is a contents of input.txt file:

c4a24534,2434b375,e750c718

Use zip() for splitting into two lists:

with open('input.txt') as f:
    i, q = zip(*((x[:4], x[4:]) for line in f for x in line.split(',')))

print i
print q

Prints:

('c4a2', '2434', 'e750')
('4534', 'b375', 'c718')

These are tuples, if you need to make lists from them, call list() on each:

print list(i)
print list(q)

Answer 2

You can use zip to separate the list into two collections.

x=[
['c4a2', '4534'], 
['2434', 'b375'],
['e750', 'c718']
]

i,q = zip(*x)

print i
print q

Result:

('c4a2', '2434', 'e750')
('4534', 'b375', 'c718')

These are tuples, though. If you really want lists, you would need to convert them.

i,q = map(list, zip(*x))
#or:
i,q = [list(tup) for tup in zip(*x)]
#or:
i,q = zip(*x)
i, q = list(i), list(q)

Answer 3

#!/usr/bin/python
import ast
file = open("file.txt","r")

i = list()
q = list()

for line in file:
    testarray = ast.literal_eval(line)
    q.append(testarray.pop())
    i.append(testarray.pop())

print(i)
print(q)

something like that ?

Answer 4

If you have read a list of lists, use zip() to turn columns into rows:

file_result = [
    ['19df', 'b35d']
    ['fafa', 'bbaf']
    ['dce9', 'cf47']
]

a, b = zip(*file_result)

Answer 5

Taking for granted that you've already parsed the file:

x = [['c4a2', '4534'], ['2434', 'b375'], ['e750', 'c718']]
i = [a[0] for a in x] # ['c4a2', '2434', 'e750']
q = [a[1] for a in x] # ['4534', 'b375', 'c718']

This takes the first and second element of each sub-list, and puts it into a new variable.