将点分隔的字符串解析为字典变量 [英] parse a dot seperated string into dictionary variable

问题描述

我有一个字符串值，

"a"
"a.b"
"b.c.d"

如何将它们转换为python字典变量，

How to convert them into python dictionary variables as,

a
a["b"]
b["c"]["d"]

字符串的第一部分(点前)将成为字典名称，其余子字符串将成为字典键

The first part of the string (before dot) will become the dictionary name and the rest of the substrings will become the dictionary keys

推荐答案

eval在这里非常危险，因为这是不受信任的输入.您可以使用regex来获取字典名称和键名，然后使用vars和dict.get查找它们.

eval is fairly dangerous here, since this is untrusted input. You could use regex to grab the dict name and key names and look them up using vars and dict.get.

import re

a = {'b': {'c': True}}

in_ = 'a.b.c'
match = re.match(
    r"""(?P<dict>      # begin named group 'dict'
          [^.]+        #   one or more non-period characters
        )              # end named group 'dict'
        \.             # a literal dot
        (?P<keys>      # begin named group 'keys'
          .*           #   the rest of the string!
        )              # end named group 'keys'""",
    in_,
    flags=re.X)

d = vars()[match.group('dict')]
for key in match.group('keys'):
    d = d.get(key, None)
    if d is None:
        # handle the case where the dict doesn't have that (sub)key!
        print("Uh oh!")
        break
result = d

# result == True

或更简单地:按点分割.

Or even more simply: split on dots.

in_ = 'a.b.c'
input_split = in_.split('.')
d_name, keys = input_split[0], input_split[1:]

d = vars()[d_name]
for key in keys:
    d = d.get(key, None)
    if d is None:
        # same as above
result = d

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