What is the usage of the “get” method in Python dictionaries?

In Python, get() is a method used to access elements in a dictionary. It takes a key as a parameter and returns the corresponding value. The get() method has two parameters: the key and a default value. If the given key exists in the dictionary, it will return the associated value; if the key does not exist, it will return the default value.

The grammar is as follows:

dictionary.get(key, default_value)

In which, key is the key to be accessed, and default_value is an optional default value. If no default value is provided, it defaults to None.

Example of usage:

person = {'name': 'John', 'age': 30, 'city': 'New York'}

name = person.get('name')
print(name)  # 输出：John

country = person.get('country', 'Unknown')
print(country)  # 输出：Unknown，因为字典中不存在'country'键

city = person.get('city', 'Unknown')
print(city)  # 输出：New York，因为字典中存在'city'键

The difference between using the get() method and directly using the index operator [] to access dictionary elements is that when the key does not exist, using the index operator will raise a KeyError exception, while the get() method will return a default value. This makes the get() method safer for handling non-existent keys.