Here is a simple solution with explanation for your query.
a=['1','2','3','4','5'] #The integer represented as a string in this list
b=[] #Fresh list
for i in a: #Declaring variable (i) as an item in the list (a).
b.append(int(i)) #Look below for explanation
print(b)
Here, append() is used to add items ( i.e integer version of string (i) in this program ) to the end of the list (b).
Note: int() is a function that helps to convert an integer in the form of string, back to its integer form.
Output console:
[1, 2, 3, 4, 5]
So, we can convert the string items in the list to an integer only if the given string is entirely composed of numbers or else an error will be generated.
You can do it simply in one line when taking input.
[int(i) for i in input().split("")]
Split it where you want.
If you want to convert a list not list simply put your list name in the place of input().split("")
.
I also want to add Python | Converting all strings in list to integers
Method #1 : Naive Method
# Python3 code to demonstrate
# converting list of strings to int
# using naive method
# initializing list
test_list = ['1', '4', '3', '6', '7']
# Printing original list
print ("Original list is : " + str(test_list))
# using naive method to
# perform conversion
for i in range(0, len(test_list)):
test_list[i] = int(test_list[i])
# Printing modified list
print ("Modified list is : " + str(test_list))
Output:
Original list is : ['1', '4', '3', '6', '7']
Modified list is : [1, 4, 3, 6, 7]
Method #2 : Using list comprehension
# Python3 code to demonstrate
# converting list of strings to int
# using list comprehension
# initializing list
test_list = ['1', '4', '3', '6', '7']
# Printing original list
print ("Original list is : " + str(test_list))
# using list comprehension to
# perform conversion
test_list = [int(i) for i in test_list]
# Printing modified list
print ("Modified list is : " + str(test_list))
Output:
Original list is : ['1', '4', '3', '6', '7']
Modified list is : [1, 4, 3, 6, 7]
Method #3 : Using map()
# Python3 code to demonstrate
# converting list of strings to int
# using map()
# initializing list
test_list = ['1', '4', '3', '6', '7']
# Printing original list
print ("Original list is : " + str(test_list))
# using map() to
# perform conversion
test_list = list(map(int, test_list))
# Printing modified list
print ("Modified list is : " + str(test_list))
Output:
Original list is : ['1', '4', '3', '6', '7']
Modified list is : [1, 4, 3, 6, 7]
If your list contains pure integer strings, the accepted awnswer is the way to go. This solution 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)
Output:
['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 {1:42, "1":84} 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", {1: 3,"1":42}, "data", "42", 98, "47.11", "of mixed",
("0", "8", {"15", "things"}, "3.141"), "types"]
converted = convertEr(data)
print(converted)
Output:
['unkind', {1: 3, '1': 42}, 'data', 42, 98, 47.11, 'of mixed',
(0, 8, {'things', 15}, 3.141), 'types'] # sets are unordered, hence diffrent order
A little bit more expanded than list comprehension but likewise useful:
def str_list_to_int_list(str_list):
n = 0
while n < len(str_list):
str_list[n] = int(str_list[n])
n += 1
return(str_list)
e.g.
>>> results = ["1", "2", "3"]
>>> str_list_to_int_list(results)
[1, 2, 3]
Also:
def str_list_to_int_list(str_list):
int_list = [int(n) for n in str_list]
return int_list
Use a list comprehension:
results = [int(i) for i in results]
e.g.
>>> results = ["1", "2", "3"]
>>> results = [int(i) for i in results]
>>> results
[1, 2, 3]
Source: Stackoverflow.com