CODEWITHSUNDEEP
pythonstringlisttype-conversionint
Cory
Cory

Reputation: 49

Sublist, converting multi digit string to list of single integers

I am trying to convert a multi digit string in sublists, into sublists of single digit integers. I would like to achieve this using simple list comprehension.

Original list:

# [[], ['0000000'], ['2200220'], ['2222220'], ['2200220'], ['2000020'], []]

Goal List:

# [[0, 0, 0, 0, 0, 0, 0], [2, 2, 0, 0, 2, 2, 0], [2, 2, 2, 2, 2, 2, 0], [2, 2, 0, 0, 2, 2, 0], [2, 0, 0, 0, 0, 2, 0]]

The following thread helped me get this far. List of list, converting all strings to int, Python 3

If I use this nested list comprehension, the strings turn into a single integer.

mylist = [[int(i) for i in s] for s in mylist]

# [[], [0], [2200220], [2222220], [2200220], [2000020], []]

I was able to do what I wanted by using two steps that involved importing a module, but this is not ideal.

import itertools

mylist = list(itertools.chain.from_iterable(mylist))

# ['0000000', '2200220', '2222220', '2200220', '2000020']

mylist_two = [[int(i) for i in str(s)] for s in mylist]

# [[0, 0, 0, 0, 0, 0, 0], [2, 2, 0, 0, 2, 2, 0], [2, 2, 2, 2, 2, 2, 0], [2, 2, 0, 0, 2, 2, 0], [2, 0, 0, 0, 0, 2, 0]]

Could anyone point me in the right direction? Thank you.

Upvotes: 0

Views: 479

Answers (3)

iGian
iGian

Reputation: 11183

Slight different way, given that each sublist contains just one element:

mylist = [[], ['0000000'], ['2200220'], ['2222220'], ['2200220'], ['2000020'], []]

[ [ int(ch) for ch in e[0] ] for e in mylist if len(e) > 0 ]

#=> [[0, 0, 0, 0, 0, 0, 0], [2, 2, 0, 0, 2, 2, 0], [2, 2, 2, 2, 2, 2, 0], [2, 2, 0, 0, 2, 2, 0], [2, 0, 0, 0, 0, 2, 0]]

Upvotes: 0

pault
pault

Reputation: 43504

A simple way is to flatten the list using a nested list comprehension, then convert each character in the string to integer.

Here's how you can modify your code:

mylist = [[], ['0000000'], ['2200220'], ['2222220'], ['2200220'], ['2000020'], []]
print([[int(z) for z in y] for x in mylist for y in x])
#[[0, 0, 0, 0, 0, 0, 0],
# [2, 2, 0, 0, 2, 2, 0],
# [2, 2, 2, 2, 2, 2, 0],
# [2, 2, 0, 0, 2, 2, 0],
# [2, 0, 0, 0, 0, 2, 0]]

Upvotes: 2

Thierry Lathuille
Thierry Lathuille

Reputation: 24232

You can simply do:

data = [[], ['0000000'], ['2200220'], ['2222220'], ['2200220'], ['2000020'], []]
out = [list(map(int, list(s[0]))) for s in data if s ]
print(out)

# [[0, 0, 0, 0, 0, 0, 0], [2, 2, 0, 0, 2, 2, 0], [2, 2, 2, 2, 2, 2, 0], [2, 2, 0, 0, 2, 2, 0], [2, 0, 0, 0, 0, 2, 0]]out = [list(s[0]) for s in data if s ]

Since strings are iterable, list('123') will create a list by iterating on the individual characters of '123', so it will return ['1', '2', '3']. We then map each individual digit to an integer.

Upvotes: 1

Related Questions