Convert a number to a list of integers

Question

How do I write the magic function below?

>>> num = 123
>>> lst = magic(num)
>>>
>>> print lst, type(lst)
[1,         


        

Answer 1

Don't use the word list as variable name! It is a name of python built in data type.

Also, please clarify your question. If you are looking for a way to create a one-member list, do the following:

a = 123
my_list = [a]

and "pythonizing" Cannonade's answer:

a = 123
my_list = [int(d) for d in str(a)]

Answer 2

for python 3.x:

num = 1234
lst = list(map(int, str(num)))

Answer 3

You could do this:

>>> num = 123
>>> lst = map(int, str(num))
>>> lst, type(lst)
([1, 2, 3], <type 'list'>)

Answer 4

You can try this:

def convert_to_list(number):
    return list(map(lambda x: int(x), str(number)))

convert_to_list(1245)

Answer 5

>>> from collections import deque
>>> def magic(num):
        digits = deque()
        while True:
            num,r = divmod(num,10)
            digits.appendleft(r)
            if num == 0:
                break
        return list(digits)

>>> magic(123)
[1, 2, 3]

According to my timings, this solution is considerably faster than the string method (magic2), even for smaller examples.

>>> def magic2(num):
        return [int(i) for i in str(num)]

Timings:

magic

>>> timeit.timeit(setup='from __main__ import magic', stmt='magic(123)')
1.3874572762508706
>>> timeit.timeit(setup='from __main__ import magic', stmt='magic(999999999)')
3.2624468999981673

magic2

>>> timeit.timeit(setup='from __main__ import magic2', stmt='magic2(123)')
3.693756106896217    
>>> timeit.timeit(setup='from __main__ import magic2', stmt='magic2(999999999)')
10.485281719412114