How to Convert a List of Numeric Strings to Integers in Python?

Converting a Python list of numeric strings to array of integers

In Python, you can convert a list of numeric strings to a list of integers by calling the int() method on every element of the list, for example, using list comprehension, like so:

items = ['5', '-7', '1', '-2']
new_list = [int(item) for item in items]

print(new_list) # [5, -7, 1, -2]

The code above would create a new list with all numeric strings in the list converted to integers. This is equivalent to the following, which uses map():

items = ['5', '-7', '1', '-2']
new_list = list(map(lambda item: int(item), items))

print(new_list) # [5, -7, 1, -2]

However, using list comprehension provides a more readable and concise syntax. For that reason, it is generally preferred and would be the recommended way.

For completeness sake, you can also achieve the same result with a simple loop:

items = ['5', '-7', '1', '-2']
new_list = []

for item in items:
    new_list.append(int(item))

print(new_list) # [5, -7, 1, -2]

However, it might not be the best choice as it would create/overwrite a variable named "item", which would persist even after the loop completes:

items = ['5', '-7', '1', '-2']
new_list = []

for item in items:
    new_list.append(int(item))

print(item) # -2

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