QuickPath

QuickPath is a package, which provides functions for easy access the elements of collection/object structures.

Motivating example

animals = [
  {
    'name': 'Wombat', 
    'avg_properties': {
      'height': {'value': 66, 'unit': 'cm'}, 
      'length':{'value': 108, 'unit': 'cm'},
      'weight': {'value': 27, 'unit': 'kg'}
    }
  },
  {
    'name': 'Duck', 
    'avg_properties': {
      'height': {'value': 62, 'unit': 'cm'}, 
      'weight': {'value': 1, 'unit': 'kg'}
    }
  },
  {
    'name': 'Dog', 
    'max_properties': {
      'height': {'value': 95, 'unit': 'cm'}, 
      'weight': {'value': 105, 'unit': 'kg'}
    }
  },
]

Let's query that above structure:

for animal in animals:
  print(animal["name"], 
        'average length', 
        animal["avg_properties"]["length"]["value"])

This code will abort with error as no the Duck has no length key. We have to add one more check.

for animal in animals:
  print(animal["name"], 
        'average length', 
        animal["avg_properties"]["length"]["value"] 
          if "length" in animal["avg_properties"] 
          else '-')

This improved code will still fail as Dog has only max_property key, we have to handle this situation too.

for animal in animals:
  if "avg_properties" in animal 
      and "length" in animal["avg_properties"]:
    print(animal["name"], 
          'average length', 
          animal["avg_properties"]["length"]["value"])
  else:
    print(animal["name"], 
          'avarage length', 
          "-")

The above scenarios can be simplified by quickpath:

from quickimport import getpath
for animal in animals:
  print(animal["name"], 
        'average length', 
        getpath(animal, 
                ("avg_properties", "length", "value"), 
                default='-'))

Alternatively, the keys can be represented as a single string:

from quickimport import getpaths
for animal in animals:
  print(animal["name"], 
        'average length', 
        getpaths(animal, 
                "avg_properties.length.value"), 
                default='-'))

Separator can be changed to any alternative characters:

from quickimport import getpaths
for animal in animals:
  print(animal["name"], 
        'average length', 
        getpaths(animal, 
                "avg_properties/length/value"), 
                default='-', 
                sep='/')

Related Work:

• dotpath is a similar, but a bit simpler solution to the problem what this package tries to achive: https://github.com/silasvasconcelos/dotpath
• DPath allow access embedded dicts with XPath like syntax: https://github.com/dpath-maintainers/dpath-python
• Benedict is a dict only solution allowing dict with hierarchical keys: https://github.com/fabiocaccamo/python-benedict
• Dict-path is one more hierarchical dict solution: https://github.com/maztohir/dict-path
• dictpath/pathable is provides a Pathlib like syntax to query dictionaries: https://github.com/p1c2u/pathable
• XPath and jsonpath have many implementation, but XML and JSON representation is requeired, respectiely.
• ObjectPath is a query language for to query object hierarchies interactively: http://objectpath.org/tutorial.html
• PythonQL allows to query object but with a special syntax which converted to Python by a preprocessor: https://github.com/pythonql/pythonql