Re: [PLUG] Python nested dict data structure

I was looking into how to make it json serializable when I wrote that but it seemed like there wasn't a way to do it without writing a custom json encoder class and forcing the caller to pass in my custom class. It would probably be easier to simply add a method to convert the whole thing back to a standard python dictionary and then serialize that.

I can write that for you if you want but it looks like you'd rather go another route. I guess for me it's just kind of interesting that in theory we could write a python class that more or less behaves like a perl object. Weak typing is a hell of a drug. I was really considering for a minute making a whole project of this and creating a package for it but it's probably not that useful anyway and I'm sure someone's already done it.

On Sat, Jul 10, 2021, 3:12 PM JP Vossen via plug <plug@lists.phillylinux.org> wrote:

On 7/10/21 1:22 PM, gary@duzan.org wrote:
> Adding "import numbers" on a line before "class PerlObject:" should do it.

Duh. Thank you, yes, that works.

Code:
```
1 #!/usr/bin/env python3
2 # dict3.py--do I REALLY have to build a CLASS just for NESTED dicts!?
3 # 2021-07-10
4 # From Luke Brooks in EM "Re: [PLUG] Python nested dict data structure"
5
6 import json # But doesn't work because PerlObject() isn't JSON serializable
7 import numbers
8
9 class PerlObject:
10
11 def __init__(self, value=None):
12 self.Value = value
13
14 def __getitem__(self, key):
15 self.checkType(dict)
16 if key not in self.Value:
17 self.Value[key] = PerlObject()
18 return self.Value[key]
19
20 def __setitem__(self, key, value):
21 self.checkType(dict)
22 if isinstance(value, PerlObject):
23 self.Value[key] = value
24 else:
25 self.Value[key] = PerlObject(value)
26
27 def __delitem__(self, key):
28 self.checkType(dict)
29 if key in self.Value:
30 del self.Value[key]
31
32 def __add__(self, other):
33 self.checkType(numbers.Number, 0)
34 if isinstance(other, PerlObject):
35 other.checkType(numbers.Number, 0)
36 return PerlObject(self.Value + other.Value)
37 return PerlObject(self.Value + other)
38
39 def checkType(self, t, dfv=None):
40 if self.Value == None:
41 if dfv != None:
42 self.Value = dfv
43 else:
44 self.Value = t()
45 elif not isinstance(self.Value, t):
46 raise Exception("Object does not support operation")
47
48 def __repr__(self):
49 return str(self)
50
51 def __str__(self):
52 return str(self.Value)
53
54 d = PerlObject()
55
56 # Main
57 company = 'Acme Inc' # Key in both (all) files
58
59 # First read file 1, containing: Company\tRegion\tOther-stuff-I-don't-care-about-here
60 d[company]['region'] = 'US'
61
62 # ...LATER...read file 2, containing *multiple records* of: Company\tthis\tthat\Counter
63 d[company]['counter'] += 2
64 d[company]['counter'] += 3
65
66 # ...STILL LATER...read file 3, containing even more crazy stuff
67 d[company]['subkey']['subsubkey'] = 'foo'
68 d[company]['subkey']['subsubint'] += 6
69
70 print(d)
71 #TypeError: Object of type 'PerlObject' is not JSON serializable
72 #print(json.dumps(d, indent=2, sort_keys=True)) # Pretty but needs: import json
```

Output:
```
$ ./dict3.py
{'Acme Inc': {'region': US, 'counter': 5, 'subkey': {'subsubkey': foo, 'subsubint': 6}}}
```

If I try to `print(json.dumps(...` I get this:
```
$ ./dict3.py
Traceback (most recent call last):
File "./dict3.py", line 71, in <module>
print(json.dumps(d, indent=2, sort_keys=True)) # Pretty but needs: import json
File "/usr/lib/python3.6/json/__init__.py", line 238, in dumps
**kw).encode(obj)
File "/usr/lib/python3.6/json/encoder.py", line 201, in encode
chunks = list(chunks)
File "/usr/lib/python3.6/json/encoder.py", line 437, in _iterencode
o = _default(o)
File "/usr/lib/python3.6/json/encoder.py", line 180, in default
o.__class__.__name__)
TypeError: Object of type 'PerlObject' is not JSON serializable
```

Which makes sense because as Luke already said, "[the class is] pretty limited in functionality so far since I made it specifically for this example."

Thanks,
JP
-- -------------------------------------------------------------------
JP Vossen, CISSP | http://www.jpsdomain.org/ | http://bashcookbook.com/
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