TypeError: argument of type ‘int’ is not iterable

The error message:

TypeError: argument of type 'int' is not iterable

occurs when you try to use an integer (int) in a context where an iterable (like a list, tuple, string, or dictionary) is expected.

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1. Causes and Solutions

Cause 1: Using in Operator on an Integer

The in operator checks if a value exists inside an iterable, but if the object is an integer, Python raises this error.

Incorrect Code:

num = 100
if 5 in num:  # TypeError
    print("Found!")

Solution: Convert num to a String or Iterable

num = "100"
if "5" in num:  # Now it's iterable
    print("Found!")  

OR

digits = [1, 0, 0]
if 5 in digits:  # Checking inside a list
    print("Found!")

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Cause 2: Checking Membership in an Integer Instead of a List or String

Trying to check if a number exists inside another number using in leads to this error.

Incorrect Code:

number = 12345
if 2 in number:  # TypeError
    print("Found!")

Solution: Convert to String or List

if "2" in str(number):  # Convert to string
    print("Found!")  # Output: Found!

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Cause 3: Iterating Over an Integer Instead of an Iterable

Looping over an integer directly is not allowed.

Incorrect Code:

num = 5
for digit in num:  # TypeError
    print(digit)

Solution: Convert to a String or Use range()

for digit in str(num):  # Convert to string
    print(digit)  # Output: 5

OR

for i in range(num):  # Works correctly
    print(i)

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Cause 4: Using int Instead of list in Functions That Expect an Iterable

Functions like sum(), max(), min(), and sorted() expect an iterable as input.

Incorrect Code:

num = 1234
print(sum(num))  # TypeError

Solution: Convert to a List of Digits

num_list = [int(digit) for digit in str(num)]  # Convert digits into a list
print(sum(num_list))  # Output: 10 (1+2+3+4)

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Cause 5: Passing an Integer Instead of a List or String to Functions

Some functions require an iterable, but if an integer is passed instead, Python raises this error.

Incorrect Code:

len(12345)  # TypeError: int is not iterable

Solution: Convert to String

print(len(str(12345)))  # Output: 5