dict – Useful code

Python – DefaultDict Object. Or how to avoid the Key Error.

Posted on May 3, 2021 by

Vitosh Posted in Python

Have you seen the error below?

Traceback (most recent call last):
  File "C:/Users/foo/PycharmProjects/pythonProject3/main.py", line 29, in <module>
    main()
  File "C:/Users/foo/PycharmProjects/pythonProject3/main.py", line 19, in main
    a['foo'] += 5
KeyError: 'foo'

Traceback (most recent call last):

File "C:/Users/foo/PycharmProjects/pythonProject3/main.py", line 29, in <module>

main()

File "C:/Users/foo/PycharmProjects/pythonProject3/main.py", line 19, in main

a['foo'] += 5

KeyError: 'foo'

Of course you have. And you know, that it is because you have written something extremely unwise like this:

    a = dict()
    a['foo'] += 5

1 2	a = dict() a['foo'] += 5

Yeah. You cannot increment the value of a non-existent key. Unless… Unless you…

Tag: dict

Python – DefaultDict Object. Or how to avoid the Key Error.