Convert all strings in a list to integers [duplicate]

Use map then list to obtain a list of integers:

list(map(int, xs)) 

In Python 2, list was unnecessary since map returned a list:

map(int, xs) 

I want to point out that pylint discourages the use of map , so prepare to use list comprehensions anyway if you ever use that standard. :)

You can simplify this answer: just always use list(map(int, results)) , it works for any Python version.

I just want to add for the map function its type is an iterable so technically if you were to iterate through it you wouldn't need to convert it into a list.

Use a list comprehension on the list xs :

[int(x) for x in xs] 

>>> xs = ["1", "2", "3"] >>> [int(x) for x in xs] [1, 2, 3] 

List comprehension is great too. To the OP - see here for to see a nice contrast of map and list comprehension: stackoverflow.com/questions/1247486/…

There are several methods to convert string numbers in a list to integers.

In Python 2.x you can use the map function:

>>> results = ['1', '2', '3'] >>> results = map(int, results) >>> results [1, 2, 3] 

Here, It returns the list of elements after applying the function.

In Python 3.x you can use the same map

>>> results = ['1', '2', '3'] >>> results = list(map(int, results)) >>> results [1, 2, 3] 

Unlike python 2.x, Here map function will return map object i.e. iterator which will yield the result(values) one by one that's the reason further we need to add a function named as list which will be applied to all the iterable items.

Refer to the image below for the return value of the map function and it's type in the case of python 3.x

The third method which is common for both python 2.x and python 3.x i.e List Comprehensions

>>> results = ['1', '2', '3'] >>> results = [int(i) for i in results] >>> results [1, 2, 3] 

You can easily convert string list items into int items using loop shorthand in python

Say you have a string result = ['1','2','3']

result = [int(item) for item in result] print(result) 

It'll give you output like

If your list contains pure integer strings, the accepted answer is the way to go. It will crash if you give it things that are not integers.

So: if you have data that may contain ints, possibly floats or other things as well - you can leverage your own function with errorhandling:

def maybeMakeNumber(s): """Returns a string 's' into a integer if possible, a float if needed or returns it as is.""" # handle None, "", 0 if not s: return s try: f = float(s) i = int(f) return i if f == i else f except ValueError: return s data = ["unkind", "data", "42", 98, "47.11", "of mixed", "types"] converted = list(map(maybeMakeNumber, data)) print(converted) 

['unkind', 'data', 42, 98, 47.11, 'of mixed', 'types'] 

To also handle iterables inside iterables you can use this helper:

from collections.abc import Iterable, Mapping def convertEr(iterab): """Tries to convert an iterable to list of floats, ints or the original thing from the iterable. Converts any iterable (tuple,set, . ) to itself in output. Does not work for Mappings - you would need to check abc.Mapping and handle things like when converting them - so they come out as is.""" if isinstance(iterab, str): return maybeMakeNumber(iterab) if isinstance(iterab, Mapping): return iterab if isinstance(iterab, Iterable): return iterab.__class__(convertEr(p) for p in iterab) data = ["unkind", , "data", "42", 98, "47.11", "of mixed", ("0", "8", , "3.141"), "types"] converted = convertEr(data) print(converted) 

['unkind', , 'data', 42, 98, 47.11, 'of mixed', (0, 8, , 3.141), 'types'] # sets are unordered, hence diffrent order