TypeError: argument of type 'int' is not iterable (Python)

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Borislav Hadzhiev

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Table of Contents #

  1. TypeError: argument of type 'int' is not iterable in Python
  2. TypeError: 'numpy.int64' object is not iterable in Python
  3. TypeError: 'int' object is not iterable in Python
  4. TypeError: 'type' object is not iterable in Python

Make sure to click on the correct subheading depending on your error message.

TypeError: argument of type 'int' is not iterable in Python #

The Python "TypeError: argument of type 'int' is not iterable" occurs when we use the membership test operators (in and not in) with an integer value.

To solve the error, correct the assignment or convert the int to a string.

typeerror argument of type int is not iterable

Here is an example of how the error occurs.

main.py
my_str = 15 # โ›”๏ธ TypeError: argument of type 'int' is not iterable print('a' in my_str)

We tried to use a membership test operator with an integer value and got the error.

Chances are you meant to use the operator with an iterable, e.g. a string or a list.

Convert the integer to a string or use a list #

One way to solve the error is to convert the integer to a string.

main.py
my_str = 15 print('a' in str(my_str)) # ๐Ÿ‘‰๏ธ False print('5' in str(my_str)) # ๐Ÿ‘‰๏ธ True

Strings are iterable, so converting the integer to a string solves the issue.

Track down where the variable got assigned an integer #

However, the best way to solve the error is to track down where the variable got assigned an int and correct the assignment.

For example, you can reassign the variable if it stores a value of an unexpected type.

main.py
my_list = 15 if not isinstance(my_list, list): my_list = [] print('a' in my_list) # ๐Ÿ‘‰๏ธ False

We check if the my_list variable doesn't store a list, and if it doesn't, we set it to an empty list before using the in operator.

You can use this approach with any other object, e.g. str, dict, tuple, etc.

main.py
my_str = 15 if not isinstance(my_str, str): my_str = "" print('a' in my_str) # ๐Ÿ‘‰๏ธ False

If the variable is not a string, we set it to an empty string.

Check if the value is not an integer before using in #

Alternatively, you can check if the value is not an int before using the in or not in operators.

main.py
my_str = 15 if not isinstance(my_str, int): print('a' in my_str) else: # ๐Ÿ‘‡๏ธ this runs print('value is an integer')

We check if the value is not an instance of the int class, and if it isn't, we use the in operator to test for membership.

However, it's safer to check if the value is of the expected type, e.g. a str, a list, or a dict.

main.py
if isinstance(my_list, list): print('a' in my_list) else: print('value is not a list')

Our if statement checks if the value is an instance of the list class, and if it is, we use the in operator.

The in operator tests for membership. For example, x in s evaluates to True if x is a member of s, otherwise it evaluates to False.

main.py
my_str = 'hello world' print('world' in my_str) # ๐Ÿ‘‰๏ธ True print('another' in my_str) # ๐Ÿ‘‰๏ธ False

x not in s returns the negation of x in s.

All built-in sequences and set types support the in and not in operators.

When used with a dictionary, the operators check for the existence of the specified key in the dict object.

The Python "TypeError: argument of type 'int' is not iterable" occurs when we use the membership test operators (in and not in) with an integer value.

To solve the error, correct the assignment or convert the int to a string.

TypeError: 'numpy.int64' object is not iterable in Python #

The Python "TypeError: 'numpy.int64' object is not iterable" occurs when we try to iterate over an integer or pass an integer to a built-in function like sum() or min().

To solve the error, iterate over an array of integers or pass an iterable to built-in methods.

typeerror-numpy-int64-object-is-not-iterable

Here is an example of how the error occurs.

main.py
import numpy as np my_int = np.int64(25) # โ›”๏ธ TypeError: 'numpy.int64' object is not iterable for i in my_int: print(i)

We tried to iterate over a numpy integer value which caused the error.

Hre is another example of how the error occurs.

main.py
import numpy as np arr = np.array([1, 2, 3]) # โ›”๏ธ TypeError: 'numpy.int64' object is not iterable for i in arr[2]: print(i)

The array element at index 2 is an integer, so we can't iterate over it.

Iterating over a range of numpy integers #

We can use the range() built-in function to iterate over a range.

main.py
import numpy as np arr = np.array([1, 2, 3]) for i in range(arr[2]): print(i) # ๐Ÿ‘‰๏ธ 0, 1, 2

If you need to iterate over an array, use a basic for loop.

main.py
import numpy as np arr = np.array([1, 2, 3]) for i in arr: print(i) # ๐Ÿ‘‰๏ธ 1, 2, 3

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

NameDescription
startAn integer representing the start of the range (defaults to 0)
stopGo up to, but not including the provided integer
stepRange will consist of every N numbers from start to stop (defaults to 1)

Passing an integer to functions that expect an iterable #

Another common cause of the error is passing an integer to the built-in constructors, e.g. list(), dict(), tuple() and set().

Here is an example.

main.py
import numpy as np int_1 = np.int64(25) int_2 = np.int64(50) # โ›”๏ธ TypeError: 'numpy.int64' object is not iterable result = sum(int_1, int_2)

Functions like sum(), max() and min() take an iterable as an argument, so we can't pass it numpy integers directly.

Instead, wrap the numpy integers into a list or an array.

main.py
import numpy as np int_1 = np.int64(25) int_2 = np.int64(50) result = sum([int_1, int_2]) print(result) # ๐Ÿ‘‰๏ธ 75

Alternatively, you can use a numpy array.

main.py
import numpy as np int_1 = np.int64(25) int_2 = np.int64(50) arr = np.array([int_1, int_2]) result = sum(arr) print(result) # ๐Ÿ‘‰๏ธ 75

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

main.py
import numpy as np arr = np.array([1, 2, 3]) # โ›”๏ธ TypeError: 'numpy.int64' object is not iterable list(arr[0]) dict(arr[0]) tuple(arr[0]) set(arr[0])

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

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

main.py
l = list(['a', 'b', 'c']) print(l) # ๐Ÿ‘‰๏ธ ['a', 'b', 'c'] d = dict(name='Bobby Hadz', age=30) print(d) # ๐Ÿ‘‰๏ธ {'name': 'Bobby Hadz', 'age': 30} t = tuple([1, 2, 3]) print(t) # ๐Ÿ‘‰๏ธ (1, 2, 3) s = set(['a', 'b', 'a']) print(s) # ๐Ÿ‘‰๏ธ {'a', 'b'}

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

If you need to iterate with both the index and the current item, use the enumerate() function.

main.py
import numpy as np arr = np.array([1, 2, 3]) for idx, el in enumerate(arr): print(idx, el) # ๐Ÿ‘‰๏ธ 0 1, 1 2, 2 3

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

main.py
my_str = 'hello' try: my_iterator = iter(my_str) for i in my_iterator: print(i) # ๐Ÿ‘‰๏ธ 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 numpy integer to the iter() function, the except block is run.

main.py
import numpy as np arr = np.array([1, 2, 3]) try: my_iterator = iter(arr[0]) for i in my_iterator: print(i) except TypeError as te: print(te) # ๐Ÿ‘‰๏ธ 'numpy.int64' 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.

The Python "TypeError: 'numpy.int64' object is not iterable" occurs when we try to iterate over an integer or pass an integer to a built-in function like sum() or min().

To solve the error, iterate over an array of integers or pass an iterable to built-in methods.

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

The Python "TypeError: 'int' object is not iterable" occurs when we try to iterate over an integer or pass an integer to a built-in function like, sum(), list() or tuple().

To solve the error, use the range() built-in function to iterate over a range or pass a list of integers to the function.

typeerror int object is not iterable

Here is an example of how the error occurs.

main.py
num = 10 # โ›”๏ธ TypeError: 'int' object is not iterable for i in num: print(i)

We are trying to iterate over an integer, but integers are not iterable.

Iterating over a range #

We can use the range() built-in function to iterate over a range.

main.py
num = 10 for i in range(num): print(i) # ๐Ÿ‘‰๏ธ 0, 1, 2, ... 8, 9

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

NameDescription
startAn integer representing the start of the range (defaults to 0)
stopGo up to, but not including the provided integer
stepRange will consist of every N numbers from start to stop (defaults to 1)

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

If values for the start and stop parameters are provided, the start value is inclusive, whereas the stop value is exclusive.

main.py
num = 5 for i in range(1, num): print(i) # ๐Ÿ‘‰๏ธ 1, 2, 3, 4

Handling the error in a try/except #

If you need to handle the error, use a try/except statement.

main.py
num = 5 try: for i in num: print(i) except TypeError: # The object is not iterable # <class 'int'> print('The object is not iterable') print(type(num))

The try statement tries to iterate over the value and if an exception is raised, the except block runs.

You can print the value and its type in the except block to debug your code.

Calling a built-in function with an integer instead of an iterable #

The error is also caused if we pass an integer to built-in functions like sum(), max() and min().

main.py
int_1 = 10 int_2 = 20 # โ›”๏ธ TypeError: 'int' object is not iterable result = sum(int_1, int_2)

These functions take an iterable as an argument and cannot be called with an integer directly.

Instead, pass a list containing the integers as an argument to the function.

main.py
int_1 = 10 int_2 = 20 # โ›”๏ธ TypeError: 'int' object is not iterable result = sum([int_1, int_2]) print(result) # ๐Ÿ‘‰๏ธ 30

Another common cause of the error is passing an integer to the built-in constructors, e.g. list(), dict(), tuple() and set().

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

main.py
num = 10 # โ›”๏ธ TypeError: 'int' object is not iterable list(num) dict(num) tuple(num) set(num)

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

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

main.py
l = list(['a', 'b', 'c']) print(l) # ๐Ÿ‘‰๏ธ ['a', 'b', 'c'] d = dict(name='Bobby Hadz', age=30) print(d) # ๐Ÿ‘‰๏ธ {'name': 'Bobby Hadz', 'age': 30} t = tuple([1, 2, 3]) print(t) # ๐Ÿ‘‰๏ธ (1, 2, 3) s = set(['a', 'b', 'a']) print(s) # ๐Ÿ‘‰๏ธ {'a', 'b'}

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

The error is commonly caused when using len() #

The error is commonly caused when using the len() built-in function.

main.py
my_str = 'hello' # โ›”๏ธ TypeError: 'int' object is not iterable for i in len(my_str): print(i)

The len function returns an integer that represents the length of the sequence.

If you need to iterate that many times, you can pass the result to the range() function.

main.py
my_str = 'hello' for i in range(len(my_str)): print(i) # ๐Ÿ‘‰๏ธ 0, 1, 2, 3, 4

If you need to iterate with both the index and the current character or element, use the enumerate() function.

main.py
my_str = 'hello' for idx, c in enumerate(my_str): print(idx, c) # ๐Ÿ‘‰๏ธ 0 h, 1 e, 2 l... my_list = ['a', 'b', 'c'] for idx, el in enumerate(my_list): print(idx, el) # ๐Ÿ‘‰๏ธ 0 a, 1 b, 2 c

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

main.py
my_str = 'hello' try: my_iterator = iter(my_str) for i in my_iterator: print(i) # ๐Ÿ‘‰๏ธ 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 an integer to the iter() function, the except block is run.

main.py
my_int = 100 try: my_iterator = iter(my_int) for i in my_iterator: print(i) except TypeError as te: print(te) # ๐Ÿ‘‰๏ธ 'int' 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.

The Python "TypeError: 'int' object is not iterable" occurs when we try to iterate over an integer or pass an integer to a built-in function like, sum(), list() or tuple().

To solve the error, use the range() built-in function to iterate over a range or pass a list of integers to the function.

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.

typeerror type object is not iterable

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

main.py
# โ›”๏ธ TypeError: 'type' object is not iterable for i in range: print(i)

We forgot to call the range function which caused the error.

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

main.py
for i in range(0, 3): # ๐Ÿ‘‰๏ธ 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:

NameDescription
startAn integer representing the start of the range (defaults to 0)
stopGo up to, but not including the provided integer
stepRange will consist of every N numbers from start to stop (defaults to 1)

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

If values for the start and stop parameters are provided, the start value is inclusive, whereas the stop value is exclusive.

Iterating over a class that doesn't implement the __iter__ method #

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

main.py
class Counter: pass # โ›”๏ธ TypeError: 'type' object is not iterable for c in Counter: print(c)

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

main.py
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) # ๐Ÿ‘‰๏ธ 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.

Checking if the object is iterable #

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

main.py
my_str = 'hello' try: my_iterator = iter(my_str) for i in my_iterator: print(i) # ๐Ÿ‘‰๏ธ 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 run.

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.

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.

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