如何在Python中从dict中检索数据？

data = {'name': 'John', 'age': 25, 'city': 'New York'}
name = data['name']  # 检索键为'name'的值
print(name)  # 输出：John

data = {'name': 'John', 'age': 25, 'city': 'New York'}
name = data.get('name')  # 检索键为'name'的值
print(name)  # 输出：John

# 指定默认值
country = data.get('country', 'Unknown')
print(country)  # 输出：Unknown

data = {'name': 'John', 'age': 25, 'city': 'New York'}
keys = list(data.keys())  # 获取所有的键
values = list(data.values())  # 获取所有的值

# 通过索引检索数据
name = values[keys.index('name')]
print(name)  # 输出：John

# 循环检索数据
for key, value in data.items():
    if key == 'name':
        print(value)  # 输出：John

data = {'name': 'John', 'age': 25, 'city': 'New York'}
if 'name' in data:
    name = data['name']
    print(name)  # 输出：John