Nested list comprehension equivalent

Question

Is it possible to replace the following code with a list comprehension expression?

input = ['1\t2,3\t4,5', '61\t7,8\t9,0']

res = []
li = [i.split() for i in input]
for i in li:
    l = [i[0]]
    l = l + [e.split(',') for e in i[1:]]
    res.append(l)

The problem is that the first element in every sublist should be treated differently than the rest of the elements.

score 2 · Accepted Answer · answered Jul 22 '12 at 08:57

2

I have to say this isn't really that Pythonic considering readability.

>>> l = ['1\t2,3\t4,5', '61\t7,8\t9,0']
>>> [[i[0]]+[e.split(',') for e in i[1:]] for i in [x.split() for x in l]]
[['1', ['2', '3'], ['4', '5']], ['61', ['7', '8'], ['9', '0']]]

answered Jul 22 '12 at 08:57

Burhan Khalid

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Then what would be a more pythonic way of doing this? – Max Jul 22 '12 at 09:21
1

I meant considering readability. Nothing "un pythonic" about the way you had it either, except maybe I wouldn't have created the intermediary list in your loop. – Burhan Khalid Jul 22 '12 at 09:46
You can do `i[:1]` instead of `[i[0]]` – jamylak Jul 22 '12 at 10:19
@Max You could use `csv` like my solution since it is a module built for reading these types of strings. – jamylak Jul 22 '12 at 10:32

score 1 · Answer 2 · answered Jul 22 '12 at 09:05

1

>>> input = ['1\t2,3\t4,5', '61\t7,8\t9,0']
>>> 
>>> [[a.split()[0]] + [b.split(',') for b in a.split()[1:]] for a in input]
[['1', ['2', '3'], ['4', '5']], ['61', ['7', '8'], ['9', '0']]]

answered Jul 22 '12 at 09:05

whtsky

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jamylak · Answer 3 · 2012-07-22T10:28:47.007

0

>>> import csv
>>> data = ['1\t2,3\t4,5', '61\t7,8\t9,0']
>>> [x[:1] + list(csv.reader(x[1:], delimiter=','))
     for x in csv.reader(data, delimiter='\t')]
[['1', ['2', '3'], ['4', '5']], ['61', ['7', '8'], ['9', '0']]]

edited Jul 22 '12 at 10:28

answered Jul 22 '12 at 10:17

jamylak

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Nested list comprehension equivalent

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