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Convert all strings in a list to int


Question

In Python, I want to convert all strings in a list to integers.

So if I have:

results = ['1', '2', '3']

How do I make it:

results = [1, 2, 3]
2018/10/08
1
622
10/8/2018 3:43:49 PM

Accepted Answer

Use the map function (in Python 2.x):

results = map(int, results)

In Python 3, you will need to convert the result from map to a list:

results = list(map(int, results))
2018/10/08
1202
10/8/2018 3:45:26 PM


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
2019/02/14

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.

2020/07/03

Source: https://stackoverflow.com/questions/7368789
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