PYTHON

check if a given key already exists in a dictionary

if 'key1' in my_dict:
    print("blah")
else:
    print("boo")

Check if a Key is Already Present in a Dictionary

my_dict = {1: 'a', 2: 'b', 3: 'c'}

if 2 in my_dict:
    print("present")

check if a given key already exists in a dictionary

d = {'a': 1, 'b': 2}
'a' in d # <== evaluates to True
'c' in d # <== evaluates to False

check if a given key already exists in a dictionary

if 'key1' in my_dict:
    ...

check if a given key already exists in a dictionary

message = "blah" if 'key1' in my_dict else "booh"
print(message)