int() argument must be a string or real number, not 'list'

int() argument must be a string or real number not, 'list' #

The Python "TypeError: int() argument must be a string, a bytes-like object or a real number, not 'list'" occurs when we pass a list to the int() class. To solve the error, access a specific item in the list and pass the item to the int() class, e.g. int(my_list[0]).

Here is an example of how the error occurs.

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my_list = ['3', '5', '8']

# ⛔️ TypeError: int() argument must be a string, a bytes-like object or a real number, not 'list'
result = int(my_list)

We passed an entire list to the int() class which caused the error.

One way to solve the error is to access the list at a specific index and pass the item to the int() class.

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my_list = ['3', '5', '8']

result = int(my_list[0])

print(result)  # 👉️ 3

If you meant to join all the items in the list into a string and convert the result to an integer, use the join() method.

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my_list = ['3', '5', '8']

my_str = ''.join(my_list)
print(my_str)  # 👉️ '358'

my_int = int(my_str)
print(my_int)  # 👉️ 358

The str.join method takes an iterable as an argument and returns a string which is the concatenation of the strings in the iterable.

Note that the method raises a TypeError if there are any non-string values in the iterable.

If your list contains numbers, or other types, convert all of the values to string before calling join().

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my_list = ['3', 5, 8]

my_str = ''.join(map(str, my_list))
print(my_str)  # 👉️ '358'

my_int = int(my_str)
print(my_int)  # 👉️ 358

The map() function takes a function and an iterable as arguments and calls the function with each item of the iterable.

You can also use a list comprehension if you need to convert all items in a list to integers.

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my_list = ['3', '5', '8']

new_list = [int(x) for x in my_list]

print(new_list)  # 👉️ [3, 5, 8]

We pass each string in the list to the int() class to convert each item to an integer.

Conclusion #

The Python "TypeError: int() argument must be a string, a bytes-like object or a real number, not 'list'" occurs when we pass a list to the int() class. To solve the error, access a specific item in the list and pass the item to the int() class, e.g. int(my_list[0]).