我有一个复杂的字典结构,我想通过一个键列表来访问它以解决正确的项目。
dataDict = {
"a":{
"r": 1,
"s": 2,
"t": 3
},
"b":{
"u": 1,
"v": {
"x": 1,
"y": 2,
"z": 3
},
"w": 3
}
}
maplist = ["a", "r"]
或
maplist = ["b", "v", "y"]
我已经编写了以下有效的代码,但如果有人有想法,我相信有更好、更有效的方法来做到这一点。
# Get a given data from a dictionary with position provided as a list
def getFromDict(dataDict, mapList):
for k in mapList: dataDict = dataDict[k]
return dataDict
# Set a given data in a dictionary with position provided as a list
def setInDict(dataDict, mapList, value):
for k in mapList[:-1]: dataDict = dataDict[k]
dataDict[mapList[-1]] = value
最佳答案
使用reduce()
遍历字典:
from functools import reduce # forward compatibility for Python 3
import operator
def getFromDict(dataDict, mapList):
return reduce(operator.getitem, mapList, dataDict)
并重用 getFromDict
来找到存储 setInDict()
值的位置:
def setInDict(dataDict, mapList, value):
getFromDict(dataDict, mapList[:-1])[mapList[-1]] = value
mapList
中除了最后一个元素之外的所有元素都需要找到“父”字典来添加值,然后使用最后一个元素将值设置为右键。
演示:
>>> getFromDict(dataDict, ["a", "r"])
1
>>> getFromDict(dataDict, ["b", "v", "y"])
2
>>> setInDict(dataDict, ["b", "v", "w"], 4)
>>> import pprint
>>> pprint.pprint(dataDict)
{'a': {'r': 1, 's': 2, 't': 3},
'b': {'u': 1, 'v': {'w': 4, 'x': 1, 'y': 2, 'z': 3}, 'w': 3}}
请注意 Python PEP8 风格指南 prescribes snake_case names for functions .以上方法同样适用于列表或字典和列表的混合,因此名称应该是 get_by_path()
和 set_by_path()
:
from functools import reduce # forward compatibility for Python 3
import operator
def get_by_path(root, items):
"""Access a nested object in root by item sequence."""
return reduce(operator.getitem, items, root)
def set_by_path(root, items, value):
"""Set a value in a nested object in root by item sequence."""
get_by_path(root, items[:-1])[items[-1]] = value
为了完成,一个删除键的函数:
def del_by_path(root, items):
"""Delete a key-value in a nested object in root by item sequence."""
del get_by_path(root, items[:-1])[items[-1]]
关于python - 通过键列表访问嵌套字典项?,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/14692690/