converting list of string to list of integer

Question

How do I convert a space separated integer input into a list of integers?

Example input:

list1 = list(input("Enter the unfriendly numbers: "))

Example conversion:

['1', '2', '3', '4', '5']  to  [1, 2, 3, 4, 5]

ch3ka · Accepted Answer · 2012-04-27T13:58:47.657

35

map() is your friend, it applies the function given as first argument to all items in the list.

map(int, yourlist)

since it maps every iterable, you can even do:

map(int, input("Enter the unfriendly numbers: "))

which (in python3.x) returns a map object, which can be converted to a list. I assume you are on python3, since you used input, not raw_input.

edited Apr 27 '12 at 13:58

answered Apr 27 '12 at 13:47

ch3ka

11,792
4
31
28

1

+1 but did you mean `map(int,yourlist)` ? – Rob I Apr 27 '12 at 13:48
do you mean `map(int, input().split())`, or does py3k automatically convert space-separated input into a list? – quodlibetor Apr 27 '12 at 14:23
no, I assumed that the digits are entered without whitespace, as the provided example suggests. In fact, I did not post this as a solution, I just wanted to point out that the second argument to map() does not have to be a list, any iterable works. – ch3ka Apr 27 '12 at 14:26

score 15 · Answer 2 · answered Apr 27 '12 at 13:48

15

One way is to use list comprehensions:

intlist = [int(x) for x in stringlist]

answered Apr 27 '12 at 13:48

Maehler

6,111
1
41
46

+1, `[int(x) for x in input().split()]` to conform OP's specs. – georg Apr 27 '12 at 14:34

score 3 · Answer 3 · answered Apr 27 '12 at 14:46

3

this works:

nums = [int(x) for x in intstringlist]

answered Apr 27 '12 at 14:46

cobie

7,023
11
38
60

score 1 · Answer 4 · answered Apr 27 '12 at 13:48

1

You can try:

x = [int(n) for n in x]

answered Apr 27 '12 at 13:48

Silviu

835
14
22

3

This doesn't work. `int` is not a method on strings. – Matt Fenwick Apr 27 '12 at 13:49
Sorry I edited it... This is actually what I meant :) – Silviu Apr 27 '12 at 13:51
It's not wrong, but I generally wouldn't reuse `x` like that. – Matt Fenwick Apr 27 '12 at 13:53
Can you give me an example why? – Silviu Apr 27 '12 at 13:55

score 1 · Answer 5 · answered May 22 '17 at 05:40

Say there is a list of strings named list_of_strings and output is list of integers named list_of_int. map function is a builtin python function which can be used for this operation.

'''Python 2.7'''
list_of_strings = ['11','12','13']
list_of_int = map(int,list_of_strings)
print list_of_int

score 0 · Answer 6 · edited Feb 19 '13 at 02:22

0

 l=['1','2','3','4','5']

for i in range(0,len(l)):
    l[i]=int(l[i])

edited Feb 19 '13 at 02:22

Rachel Gallen

27,943
21
72
81

answered Apr 27 '12 at 15:46

Chandan Cm

1
3

okm · Answer 7 · 2012-04-28T02:32:44.887

Just curious about the way you got '1', '2', '3', '4' instead of 1, 2, 3, 4. Anyway.

>>> list1 = list(input("Enter the unfriendly numbers: "))
Enter the unfriendly numbers: 1, 2, 3, 4
>>> list1 = list(input("Enter the unfriendly numbers: "))
Enter the unfriendly numbers: [1, 2, 3, 4]
>>> list1
[1, 2, 3, 4]
>>> list1 = list(input("Enter the unfriendly numbers: "))
Enter the unfriendly numbers: '1234'
>>> list1 = list(input("Enter the unfriendly numbers: ")) 
Enter the unfriendly numbers: '1', '2', '3', '4'
>>> list1
['1', '2', '3', '4']

Alright, some code

>>> list1 = input("Enter the unfriendly numbers: ")
Enter the unfriendly numbers: map(int, ['1', '2', '3', '4'])
>>> list1
[1, 2, 3, 4]

converting list of string to list of integer

7 Answers7

Linked