【Python 学习笔记】dictionary unpacking

what is dictionary unpacking?

Dictionary unpacking is a Python feature that allows you to extract key-value pairs from a dictionary and:

1. Pass them as arguments to a function using **

   def greet(name, age):
       print(f"Hello, my name is {name} and I'm {age} years old.")
   
   person = {"name": "Alice", "age": 30}
   greet(**person)  # Unpacks keys as argument names

2. Merge dictionaries / Create new dictionaries from existing ones

defaults = {"color": "blue", "size": "medium"}
custom = {"size": "large"}

combined = {**defaults, **custom}
print(combined)  # {'color': 'blue', 'size': 'large'}

dict1 = {"a": 1}
dict2 = {"b": 2}
new_dict = {**dict1, **dict2, "c": 3}
print(new_dict)  # {'a': 1, 'b': 2, 'c': 3}

• ** is used to unpack a dictionary's key-value pairs:

• It's useful for function calls and dictionary composition

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