使用推导将 Python 字典数组转换为 Python 字典

Question

我有一个 Python 字典数组，如下所示：

[
 {
  "pins": [1,2],
  "group": "group1"
 },
 {
  "pins": [3,4],
  "group": "group2"
 }
]

我想把这个字典数组转换成下面的字典：

{ 1: "group1", 2: "group1", 3: "group2", 4: "group2" }

我编写了以下双 for 循环来完成此操作，但很好奇是否有更有效的方法来执行此操作（也许是一种理解？）：

new_dict = {}
for d in my_array:
    for pin in d['pins']:
        new_dict[pin] = d['group']

Answer 1

让我们试试字典理解：

new_dict = {
    k : arr['group'] for arr in my_array for k in arr['pins']
}

这相当于：

new_dict = {}
for arr in my_array:
    for k in arr['pins']:
        new_dict[k] = arr['group']

print(new_dict)
{1: 'group1', 2: 'group1', 3: 'group2', 4: 'group2'}