从出现在给定列表中的键中提取子字典

Question

考虑一下我的字典如下：

{1 =＆gt; a，2 =＆gt; b，3 =＆gt; c，4 =＆gt; d}

和一个如下所示的列表：

[1,2,3]

是否有一种方法可以返回仅包含

的子字典

{1 =＆gt; a，2 =＆gt; b，3 =＆gt; c}

Answer 1

常规字典理解会这样做：

d = {1: 'a', 2: 'b', 3: 'c', 4: 'd'}
keys = [1, 2, 3]

dct = {key: d[key] for key in keys}
print(dct)  # {1: 'a', 2: 'b', 3: 'c'}

有两种处理keys中不在原始字典中的键的方法：

keys = [1, 2, 3, 7]

# default value None
dct = {key: d[key] if key in d else None for key in keys}
print(dct)  # {1: 'a', 2: 'b', 3: 'c', 7: None}

# ignore the key if it is not in the original dict
dct = {key: d[key] for key in set(keys).intersection(d.keys())}
print(dct)  # {1: 'a', 2: 'b', 3: 'c'}