Parse logical JSON data in Python

Question

I wonder if there exists some library to parse a JSON that contains logical operators to transform it into a flat query string.

Let's say as input I get:

{
    "Children":[
       {
          "ID":1,
       },
       {
          "ID":2,
       },
       {
          "Children":[
             {
                "ID":3,
             },
             {
                "ID":4,
             }
          ],
          "Type":"Or"
       }
    ],
    "Type":"And"
 }

And I want to convert it into simply:

(3 Or 4) AND 1 And 2

How would you do this in Python?

How did the all caps AND get in there?

Ben
– Ben

2020-08-26 21:24:11 +00:00
Commented Aug 26, 2020 at 21:24 — Ben
– Ben, Commented Aug 26, 2020 at 21:24

rici · Accepted Answer · 2020-08-27 15:53:13Z

2

It depends on what your precise expectations are; in particular, this problem is a lot easier if you're OK with redundant parentheses.

Here's a simple recursive function with inadequate error checking (i.e. it's likely to raise an exception if the JSON doesn't precisely conform to expectations):

def json_to_formula(j):
    if 'Children' in j:                                                                
        return '(' + f" {j['Type']} ".join(map(json_to_formula,
                                           j['Children'])) + ')'
    else:
        return str(j['ID'])

edited Aug 27, 2020 at 15:53

answered Aug 26, 2020 at 23:04

rici

243k30 gold badges263 silver badges364 bronze badges

Sign up to request clarification or add additional context in comments.

6 Comments

HansHupe Over a year ago

Thx, but what is f in the statement?

rici Over a year ago

@hanshupe: A copy and paste error. Sorry. At the last minute, I thought that f wasn't a very good name for the function, but I copied the old function body instead of the fixed one.

HansHupe Over a year ago

there still one f :)

rici Over a year ago

@HansHupe: f"..." is a Python 3 formatted string literal ("f-string")

rici Over a year ago

@HansHupe: Cool. But remember that it is only a rough guide :-). You'll need to adapt it as you add operator types. (For example, using join works fine for operators like And and Or, but it's not correct for unary operators like Not.)

|

Collectives™ on Stack Overflow

Parse logical JSON data in Python

1 Answer 1

6 Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

6 Comments

Your Answer

Sign up or log in

Post as a guest

Related