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Description
Withreprlib.Repr, it's possible to print object representations with a limit of recursive depth to increase readability of large objects. "This is used in the Python debugger and may be useful in other contexts as well."[1] For example, I'm usingreprlib to log lines for debugging. In the same line of thought, it makes sense to be able to format the output to increase readability even further. One measure to do so is to insert line breaks with indentation.
Example
>>>example= [1, [2,"foo",b"bar", {"a":1,"b":"abc def ghi","c": {1:2,3:4,5: [],6: {}}}],3]
At first glance,pprint.PrettyPrinter might be an alternative solution:
>>>importpprint>>>pprint.pprint(example,indent=4)[1, [2,'foo',b'bar', {'a':1,'b':'abc def ghi','c': {1:2,3:4,5: [],6: {}}}],3]>>>pprint.pprint(example,indent=4,depth=3)[1, [2,'foo',b'bar', {'a':1,'b':'abc def ghi','c': {...}}],3]
However, in the first example above, the innerdict has not been expanded by line breaks and indentation. In the second example, after reducingdepth, everything is suddenly printed onto one line only. This is the case, because the motivation and goal ofpprint is to optimize output for a givenwidth topretty print - not to produce consistent output for debugging purposes. This becomes even more apparent when reducingwidth:
>>>pprint.pprint(example,indent=4,depth=3,width=10)[1, [2,'foo',b'bar', {'a':1,'b':'abc ''def ''ghi','c': {1:2,3:4,5: [ ],6: { }}}],3]
Note how strings that are too long forwidth, like"abc def ghi" inexample, get split into multiple lines. This is not optimal for logging output where the width of the output (i.e. the actual line length) is usually not restricted.
Usingjson.dumps produces a similar output as the requested indentation feature forreprlib:
>>>importjson>>>print(json.dumps({"a":1,"b": [2,3]},indent=4)){"a":1,"b": [2,3 ]}
However, it is subject to the known restrictions when converting Python objects to JSON:
>>>json.dumps(example)Traceback (mostrecentcalllast):File"<stdin>",line1,in<module>File"/usr/lib/python3.9/json/__init__.py",line231,indumpsreturn_default_encoder.encode(obj)File"/usr/lib/python3.9/json/encoder.py",line199,inencodechunks=self.iterencode(o,_one_shot=True)File"/usr/lib/python3.9/json/encoder.py",line257,initerencodereturn_iterencode(o,0)File"/usr/lib/python3.9/json/encoder.py",line179,indefaultraiseTypeError(f'Object of type{o.__class__.__name__} 'TypeError:Objectof typebytesisnotJSONserializable
Therefore, it would be useful to add the following indentation feature toreprlib:
>>>importreprlib>>>print(reprlib.repr(example))# regular output[1, [2,'foo',b'bar', {'a':1,'b':'abc def ghi','c': {1:2,3:4,5: [],6: {}}}],3]>>>reprlib.aRepr.indent=4>>>print(reprlib.repr(example))# output with 4 spaces indentation[1, [2,'foo',b'bar', {'a':1,'b':'abc def ghi','c': {1:2,3:4,5: [],6: {}, }, }, ],3,]>>>reprlib.aRepr.maxlevel=3>>>print(reprlib.repr(example))# same as above, but with reduced depth[1, [2,'foo',b'bar', {'a':1,'b':'abc def ghi','c': {...}, }, ],3,]>>>reprlib.aRepr.indent="........">>>print(reprlib.repr(example))# custom indentation string[........1,........[................2,................'foo',................b'bar',................{........................'a':1,........................'b':'abc def ghi',........................'c': {...},................},........],........3,]