defining an appropriate variable name

Question

How can i catch this very basic error before it occurs ?

# create a variable
str = 10
print(str)
print(type(str))

# change from integer to string
str = str(str)
print(str)

The error is:

'int' object is not callable

I would assert that str is a keyword and a standard linter should pick this up, but my linter does not because str is in fact not a keyword (https://realpython.com/lessons/reserved-keywords/).

The same is true for int, list etc.

So how to catch or prevent this error before it occurs ?

Answer 1

The str you are using is a function in python. So when you are assigning str a value, you have overridden the function address stored in str with some value. So the str is no more a function. So when you tried to call str() it returned the error.

Look at the below output for better understanding.

>>> str(123)
'123'

>>> str = 4

>>> str(123)
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
TypeError: 'int' object is not callable

This output is from python command line interpreter. Hope this helped.