Python把三个字典合并成一个字典的常用方法

# 示例代码
config = {'host': 'localhost', 'port': 8080}
settings = {'port': 9090, 'debug': True}
overrides = {'debug': False, 'timeout': 30}

merged = {**config, **settings, **overrides}
print(merged)  # 输出：{'host': 'localhost', 'port': 9090, 'debug': False, 'timeout': 30}

# 示例代码
base = {'a': 1, 'b': 2}
ext1 = {'b': 3, 'c': 4}
ext2 = {'d': 5}

# 先复制基础字典避免污染
result = base.copy()
result.update(ext1)
result.update(ext2)
print(result)  # 输出：{'a': 1, 'b': 3, 'c': 4, 'd': 5}

# 示例代码
data1 = {'x': 10, 'y': 20}
data2 = {'y': 25, 'z': 30}
data3 = {'w': 40}

merged = {k: v for d in [data1, data2, data3] for k, v in d.items()}
print(merged)  # 输出：{'x': 10, 'y': 25, 'z': 30, 'w': 40}

from collections import ChainMap

defaults = {'theme': 'light', 'lang': 'en'}
user1 = {'theme': 'dark', 'font': 'monospace'}
user2 = {'lang': 'zh'}

# 创建视图（user2优先级最高）
profile_view = ChainMap(user2, user1, defaults)

# 实际获取值
print(profile_view['theme'])  # 输出：dark（来自user1）
print(profile_view['lang'])   # 输出：zh（来自user2）

merged = {**d1, **d2, **d3}  # 自动覆盖
# 或手动处理
merged = d1.copy()
for k, v in d2.items():
    merged[k] = v if k != 'sensitive_key' else 'default'

from collections import ChainMap
def merge_dicts(*dicts):
    result = {}
    for d in dicts:
        for k, v in d.items():
            if isinstance(v, dict) and k in result and isinstance(result[k], dict):
                result[k] = merge_dicts(result[k], v)
            else:
                result[k] = v
    return result

# 测试
n1 = {'a': {'x': 1}}
n2 = {'a': {'y': 2}, 'b': 3}
n3 = {'a': {'z': 3}, 'c': 4}
print(merge_dicts(n1, n2, n3))  # 嵌套合并成功