Solve - TypeError: 'type' object is not iterable in Python

Solve - TypeError: 'type' object is not iterable in Python #

The Python "TypeError: 'type' object is not iterable" occurs when we try to iterate over a class that is not iterable, e.g. forget to call the range() function. To solve the error, make the class iterable by implementing the __iter__() method.

Here is an example of how the error occurs when the range function.

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# ⛔️ TypeError: 'type' object is not iterable
for i in range:
    print(i)

If you use the range function, make sure to call it.

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for i in range(0, 3):  # 👉️ 0, 1, 2
    print(i)

The range class is commonly used for looping a specific number of times in for loops and takes the following parameters:

If you only pass a single argument to the range() constructor, it is considered to be the value for the stop parameter.

You will also get the error if you try to iterate over a class that doesn't implement the __iter__() method.

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class Counter:
    pass


# ⛔️ TypeError: 'type' object is not iterable
for c in Counter:
    print(c)

If you need to make the class iterable, implement the __iter__ method.

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class Counter:
    def __init__(self, start, stop):
        self.current = start - 1
        self.stop = stop

    def __iter__(self):
        return self

    def __next__(self):
        self.current += 1
        if self.current < self.stop:
            return self.current
        raise StopIteration


for c in Counter(0, 4):
    print(c)  # 👉️ 0, 1, 2, 3

The __iter__() method is implicitly called at the start of loops and returns the iterator object.

The __next__() method is implicitly called at each loop increment and returns the next value.

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 class to the iter() function, the except block is ran.

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.