Re: [PLUG] Python nested dict data structure

[JP Vossen via plug <plug@lists.phillylinux.org>]

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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