one liner for converting the nth element of a list to a integer

Question

I am trying to get the first (or any) element of a list to integer form.

my_list = ['10','Sally']

I tried:

my_list = map(int, ['10','Sally'][0])

but the output of it is:

<map object at 0x7f3549b8aa58>

How can I fix my code to change it, so that in a one line expression my_list is equal to [10,'Sally']?

Possible duplicate of [Getting a map() to return a list in Python 3.x](http://stackoverflow.com/questions/1303347/getting-a-map-to-return-a-list-in-python-3-x) — OneCricketeer, Dec 23 '16 at 02:56
You are mapping `int` over `['10','Sally'][0]`, which is only `'10'`,by the way — OneCricketeer, Dec 23 '16 at 02:57
Yes the result would be `[1, 0]` maybe not what you expected? — Paul Rooney, Dec 23 '16 at 02:59
Why do you think you need to use `map()` if you just want to change one element? — Barmar, Dec 23 '16 at 03:00

Psidom · Accepted Answer · 2016-12-23T03:04:51.863

3

You could do something like this:

[int(x) if x.isdigit() else x for x in my_list]
# [10, 'Sally']

Or maybe (Convert the nth element of a list to integer):

n = 0
[int(v) if i == n else v for i, v in enumerate(my_list)]
# [10, 'Sally']

edited Dec 23 '16 at 03:04

answered Dec 23 '16 at 03:01

Psidom

What if `i` is not a string (i.e., doesn't have an `isdigit()` method)? – elethan Dec 23 '16 at 03:04
1

@elethan Right. There are a lot of assumptions to be made here. A list can contain anything. Without a clearer context, this problem is difficult to touch. – Psidom Dec 23 '16 at 03:09
why do you loop through if you only want to change one thing? – PAS Dec 24 '16 at 02:38
That is a good point actually. you can just do `my_list[0] = int(my_list[0])` this convert the 0th element to int in place. – Psidom Dec 24 '16 at 03:01

1 Answers1