从Python字典中获取值

my_dict = {'name': 'Alice', 'age': 25, 'city': 'New York'}
value = my_dict['name']  # 获取键为'name'的值
print(value)  # 输出: Alice

value = my_dict.get('name')  # 获取键为'name'的值，如果不存在则返回None
print(value)  # 输出: Alice

value = my_dict.get('gender')  # 获取不存在的键'gender'的值
print(value)  # 输出: None

value = my_dict.get('gender', 'Unknown')  # 获取不存在的键'gender'的值，返回默认值'Unknown'
print(value)  # 输出: Unknown

if 'name' in my_dict:
    value = my_dict['name']
    print(value)  # 输出: Alice
else:
    print("Key not found")

try:
    value = my_dict['gender']  # 'gender'键不存在
except KeyError:
    print("Key not found")

my_dict = {1: 'Alice', 2: 'Bob'}
value = my_dict['1']  # 这里使用了字符串而不是整数