30秒学会 Python 片段 – Get nested value

Retrieves the value of the nested key indicated by the given selector list from a dictionary or list.

• Use functools.reduce() to iterate over the selectors list.
• Apply operator.getitem() for each key in selectors, retrieving the value to be used as the iteratee for the next iteration.

代码实现

from functools import reduce
from operator import getitem

def get(d, selectors):
  return reduce(getitem, selectors, d)

使用样例

users = {
  'freddy': {
    'name': {
      'first': 'fred',
      'last': 'smith'
    },
    'postIds': [1, 2, 3]
  }
}
get(users, ['freddy', 'name', 'last']) # 'smith'
get(users, ['freddy', 'postIds', 1]) # 2

翻译自：https://www.30secondsofcode.org/python/s/get