Call int function on every list element

Question

I have a list with numeric strings  like so   numbers     1    5    10    8      I would like to convert every list element to integer  so it would look like this   numbers    1  5  10  8     I could do it using a loop  like so   new numbers       for n in numbers      new numbers append int n    numbers   new numbers    Does it have to be so ugly  I m sure there is a more pythonic way to do this in a one line of code  Please help me out

User · Answer

If you are intending on passing those integers to a function or method, consider this example:

sum(int(x) for x in numbers)

This construction is intentionally remarkably similar to list comprehensions mentioned by adamk. Without the square brackets, it's called a generator expression, and is a very memory-efficient way of passing a list of arguments to a method. A good discussion is available here: Generator Expressions vs. List Comprehension

User · Answer

This is what list comprehensions are for   numbers     int x  for x in numbers

User · Answer

Another way   for i  v in enumerate numbers   numbers i    int v

User · Answer

just a point   numbers    int x  for x in numbers    the list comprehension is more natural  while  numbers   map int  numbers    is faster    Probably this will not matter in most cases  Useful read  LP vs map

User · Answer

Thought I d consolidate the answers and show some timeit results   Python 2 sucks pretty bad at this  but map is a bit faster than comprehension   Python 2 7 13  v2 7 13 a06454b1afa1  Dec 17 2016  20 42 59   MSC v 1500 32 bit  Intel   on win32 Type  copyright    credits  or  license    for more information   gt  gt  gt  import timeit  gt  gt  gt  setup      import random random seed 10  l    str random randint 0  99   for i in range 100       gt  gt  gt  timeit timeit   int v  for v in l    setup  116 25092001434314  gt  gt  gt  timeit timeit  map int  l    setup  106 66044823117454   Python 3 is over 4x faster by itself  but converting the map generator object to a list is still faster than comprehension  and creating the list by unpacking the map generator  thanks Artem   is slightly faster still   Python 3 6 1  v3 6 1 69c0db5  Mar 21 2017  17 54 52   MSC v 1900 32 bit  Intel   on win32 Type  copyright    credits  or  license    for more information   gt  gt  gt  import timeit  gt  gt  gt  setup      import random random seed 10  l    str random randint 0  99   for i in range 100       gt  gt  gt  timeit timeit   int v  for v in l    setup  25 133059591551955  gt  gt  gt  timeit timeit  list map int  l     setup  19 705547827217515  gt  gt  gt  timeit timeit    map int  l     setup  19 45838406513076   Note  In Python 3  4 elements seems to be the crossover point  3 in Python 2  where comprehension is slightly faster  though unpacking the generator is still faster than either for lists with more than 1 element

User · Answer

In Python 2 x another approach is to use map   numbers   map int  numbers    Note  in Python 3 x map returns a map object which you can convert to a list if you want   numbers   list map int  numbers

User · Answer

Another way to make it in Python 3   numbers     map int  numbers

[python] Call int() function on every list element?

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