pythondictionarynull-coalescing

Null coalescing on a dict entry in python

So, I'm aware that, in Python I can do this:

variable_name = other_variable or 'something else'

...and that that will assign 'something else' to variable_name if other_variable is falsy, and otherwise assign other_variable value to variable.

Can I do a nice succinct similar thing with a dict:

variable_name = my_dict['keyname'] or 'something else'

...or will a non-existent keyname always raise an error, cause it to fail?

Solution

  • You will see KeyError if 'keyname' does not exist in your dictionary. Instead, you can use:

    variable_name = my_dict.get('keyname', False) or 'something else'

    With this logic, 'something else' is assigned when either 'keyname' does not exist or my_dict['keyname'] is Falsy.