TypeError: 'bool' object is not iterable in Python

TypeError: 'bool' object is not iterable in Python #

The Python "TypeError: 'bool' object is not iterable" occurs when we try to iterate over a boolean value (True or False) instead of an iterable (e.g. a list). To solve the error, track down where the variable got assigned a boolean and correct the assignment.

Here is an example of how the error occurs.

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my_bool = True

# ⛔️ TypeError: 'bool' object is not iterable
for i in my_bool:
    print(i)

We are trying to iterate over a boolean (True or False), but booleans are not iterable.

Make sure you aren't reassigning an iterable to a boolean somewhere by mistake.

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my_list = ['a', 'b', 'c']

# 👇️ reassigned to boolean value by mistake
my_list = True

# ⛔️ TypeError: 'bool' object is not iterable
for i in my_list:
    print(i)

We initially set the my_list variable to a list but later reassigned it to a boolean which caused the error.

The following 4 calls to the built-in constructors cause the error.

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my_bool = False

# ⛔️ TypeError: 'bool' object is not iterable
list(my_bool)

dict(my_bool)

tuple(my_bool)

set(my_bool)

To solve the error, we have to correct the assignment and figure out where the boolean value is coming from.

Here are working examples of using the 4 built-ins.

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l = list(['a', 'b', 'c'])
print(l)  # 👉️ ['a', 'b', 'c']

d = dict(name='Alice', age=30)
print(d)  # 👉️ {'name': 'Alice', 'age': 30}

t = tuple([1, 2, 3])
print(t)  # 👉️ (1, 2, 3)

s = set(['a', 'b', 'a'])
print(s)  # 👉️ {'a', 'b'}

You have to figure out where the boolean value came from and correct the assignment.

If you need to check if an object is iterable, use a try/except statement.

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my_str = 'hello'

try:
    my_iterator = iter(my_str)

    for i in my_iterator:
        print(i) # 👉️ h, e, l, l, o
except TypeError as te:
    print(te)

The iter() function raises a TypeError if the passed in value doesn't support the __iter__() method or the sequence protocol (the __getitem__() method).

If we pass a non-iterable object like a boolean to the iter() function, the except block is run.

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my_bool = False

try:
    my_iterator = iter(my_bool)

    for i in my_iterator:
        print(i)
except TypeError as te:
    print(te)  # 👉️ 'bool' object is not iterable

Examples of iterables include all sequence types (list, str, tuple) and some non-sequence types like dict, file objects and other objects that define an __iter__() or a __getitem__() method.

Conclusion #

The Python "TypeError: 'bool' object is not iterable" occurs when we try to iterate over a boolean value (True or False) instead of an iterable (e.g. a list). To solve the error, track down where the variable got assigned a boolean and correct the assignment.