d = dict.fromkeys((i**2 for i in range(1,5)),1) print(d) print(5 in d) #quiker way to check the key # comprehension items = [('a', 1), ('b',2), ('e',3)] my_dict = {key: value for key,value in items} print(my_dict) transformed_dict = {k.upper(): v*2 for k, v in my_dict.items()} print(transformed_dict) my_dict = {x: x**2 for x in range(5)} print(my_dict) nested_dict = {x: {y: x*y for y in range(1, 4)} for x in range(1,4)} print(nested_dict) # tuples in Python are immutable, you cannot directly change the 'e' value inside items. # However, because items is a list of tuples, you can replace the entire tuple by rebuilding the dictionary. original_dict = {key if key != 'e' else 'c': value for key, value in items} print(original_dict)