How to convert a string of space- and comma-separated numbers into a list of int

Question

I have a string of numbers like so:

example_string = '0, 0, 0, 11, 0, 0, 0, 0, 0, 19, 0, 9, 0, 0, 0, 0, 0, 0, 11'

I would like to convert it to a list:

example_list = [0, 0, 0, 11, 0, 0, 0, 0, 0, 19, 0, 9, 0, 0, 0, 0, 0, 0, 11]

I tried this code:

example_list = []
for x in example_string:
    example_list.append(int(x))

Obviously it does not work, as the string contains spaces and commas. However, even if I remove those, the individual digits of the numbers get converted, giving a result like [0, 0, 0, 0, 1, 1, 0, 0, 0, 0, 0, 1, 9, 0, 9, 0, 0, 0, 0, 0, 0, 1, 1].

How can I get the desired result?

_{See also: How to split a string of space separated numbers into integers? . This question adds a small additional consideration: since int can accept leading and trailing whitespace, there is reason to split on just , rather than , .}

_{The obvious approach to this problem is a common combination of simple tasks:}

_{However, depending on the exact requirements, it can be addressed in other ways. For some cases, the split step may be sufficient on its own. There are other approaches, given in some answers here, to produce different output besides a native Python list - for example, using the standard library array.array, or a NumPy array.}

_{Alternately, the problem can be seen as a special case of How to extract numbers from a string in Python? .}

Somewhat related: [How to split by comma and strip white spaces in Python?](https://stackoverflow.com/questions/4071396) — Karl Knechtel, May 18 '23 at 22:44

Martijn Pieters · Accepted Answer · 2020-09-26T17:00:54.383

98

Split on commas, then map to integers:

map(int, example_string.split(','))

Or use a list comprehension:

[int(s) for s in example_string.split(',')]

The latter works better if you want a list result, or you can wrap the map() call in list().

This works because int() tolerates whitespace:

>>> example_string = '0, 0, 0, 11, 0, 0, 0, 0, 0, 19, 0, 9, 0, 0, 0, 0, 0, 0, 11'
>>> list(map(int, example_string.split(',')))  # Python 3, in Python 2 the list() call is redundant
[0, 0, 0, 11, 0, 0, 0, 0, 0, 19, 0, 9, 0, 0, 0, 0, 0, 0, 11]
>>> [int(s) for s in example_string.split(',')]
[0, 0, 0, 11, 0, 0, 0, 0, 0, 19, 0, 9, 0, 0, 0, 0, 0, 0, 11]

Splitting on just a comma also is more tolerant of variable input; it doesn't matter if 0, 1 or 10 spaces are used between values.

edited Sep 26 '20 at 17:00

answered Oct 12 '13 at 12:52

Martijn Pieters

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For the python3, you have to change `map(int, example_string.split(','))` to `list(map(int, example_string.split(',')))`. – Tengerye Sep 13 '18 at 01:11
1

@Tengerye: that depends; if you only need an iterable the `map()` object is fine as it is. – Martijn Pieters Sep 13 '18 at 08:34
Thanks a million!!!! – Emjey Dec 05 '19 at 18:14

score 14 · Answer 2 · answered Oct 12 '13 at 12:55

14

I guess the dirtiest solution is this:

list(eval('0, 0, 0, 11, 0, 0, 0, 11'))

answered Oct 12 '13 at 12:55

hendrik

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If the original string of numbers was stored in "python format", this solution will actually adapt to whatever type of data is stored. '0, 0, 0, 11' will map to int type and '0.12, 0.1, 1.2' will map to float type without having to explicitly code for it. – Marcos Nov 10 '16 at 07:56
3

It could be dirtier, but it's dirty enough to earn you my downvote. Why even post a horrible solution like that? – Aran-Fey Jun 03 '18 at 07:09

score 7 · Answer 3 · edited Aug 02 '23 at 18:34

7

It should work:

example_string = '0, 0, 0, 11, 0, 0, 0, 0, 0, 19, 0, 9, 0, 0, 0, 0, 0, 0, 11'
example_list = [int(k) for k in example_string.split(',')]

edited Aug 02 '23 at 18:34

Peter Mortensen

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answered Oct 12 '13 at 12:53

lucemia

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score 7 · Answer 4 · edited Oct 08 '14 at 15:49

7

number_string = '0, 0, 0, 11, 0, 0, 0, 0, 0, 19, 0, 9, 0, 0, 0, 0, 0, 0, 11'

number_string = number_string.split(',')

number_string = [int(i) for i in number_string]

edited Oct 08 '14 at 15:49

Edd

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answered Oct 08 '14 at 15:12

Rohit Singh

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Hey Rohit :). Welcome to SO. Do you mind adding a bit explanations to your code? So the next guys coming in have a better idea of what you're doing with your answer :). – Patrice Oct 08 '14 at 15:17

score 6 · Answer 5 · edited Aug 02 '23 at 18:35

6

You can also use a list comprehension on split string:

[ int(x) for x in example_string.split(',') ]

edited Aug 02 '23 at 18:35

Peter Mortensen

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answered Oct 12 '13 at 12:53

lejlot

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score 2 · Answer 6 · edited Aug 02 '23 at 18:36

2

Try this:

import re
[int(s) for s in re.split('[\s,]+',example_string)]

edited Aug 02 '23 at 18:36

Peter Mortensen

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answered Oct 12 '13 at 12:54

Charles JOUBERT

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How to convert a string of space- and comma-separated numbers into a list of int

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