parse a dot seperated string into dictionary variable

Question

I have string values as,

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

How to convert them into python dictionary variables as,

a
a[\"b\"]
b[\"c\"][\         


        

Answer 1

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      # begin named group 'dict'
          [^.]+        #   one or more non-period characters
        )              # end named group 'dict'
        \.             # a literal dot
        (?P      # 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

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