Defaultdict return key as default [duplicate]

Question

Say you have a dict called mydict defined below, and you look for a key called 'D'.

mydict = {'A':'a',
          'B':'b',
          'C':'c'}
mydict['D']

The desired output should be 'D', the exact output you entered. Is there a way to do this with default dict?

Answer 1

As I mentioned in a comment, you can define your own dictionary subclass that does what you want (simply echos missing keys — it doesn't add them):

class MyDefaultDict(dict):
    def __missing__(self, key):
        return key


mydict = MyDefaultDict({'A':'a',
                        'B':'b',
                        'C':'c'})

print(f"{mydict['D']=}")  # -> mydict['D']='D'