TypeError: ‘int’ object is not iterable

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This error occurs when you try to iterate over an integer in Python. To fix this, make sure anything after the in operator in Python is an iterable, such as a list. If you’re trying to use the integer to determine the number of times you’d like a for loop to run, use the range() function on it to produce a list of the numbers you want to iterate over.

Problem: you are using an integer in a for loop

The most common cause of this error is trying to use an integer directly after the in operator in a for loop.

Check out the example below:

foo = 3

for i in foo:
    print(i)
Python

We define a variable foo and assign the value 3 to it. Then, we try to iterate over it, which causes the following error:

Traceback (most recent call last):
  File "/home/user/main.py", line 3, in <module>
    for i in foo:
TypeError: 'int' object is not iterable

This is happening because in expects an iterable. You’re probably trying to run the loop foo times, and instead of passing a range of numbers to iterate over, you passed just the number instead. Luckily this is very easy to fix!

Solution: use the range function to make it iterable

Python has a built in function that does exactly what you need. All you have to do to fix the above example is call the range function on foo and you’re good to go:

foo = 3

for i in range(foo):
    print(i)
Python

The output, as expected, will give you a range of numbers starting with zero, up to but not including the value you called range on. Below is the output:

0
1
2

It’s for this reason range is frequently used in for loops to set how many times the loop will run.

And just in case you were curious, the range function does not return a list, it actually returns a range object, so range(), while it is a function, is also a constructor that returns an object:

>>> type(range(2))
<class 'range'>
Python

Conclusion

The Python error “TypeError: ‘int’ object is not iterable” means you tried to iterate over an integer. The best way to fix this, if you’re trying to use it as the number of times you want a for loop to run, is to use the range() function to turn that integer into an iterable.