sciris.sc_nested¶
Nested dictionary functions.
Functions
Flatten nested dictionary |
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Get the value for the given list of keys |
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Return a list of all the twigs in the current dictionary |
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Little functions to get and set data from nested dictionaries. |
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Merge different nested dictionaries |
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Zip list of lists in order |
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Find a key or attribute within a dictionary or object. |
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Set the value for the given list of keys |
- getnested(nesteddict, keylist, safe=False)[source]¶
Get the value for the given list of keys
>>> sc.getnested(foo, ['a','b'])
See sc.makenested() for full documentation.
- setnested(nesteddict, keylist, value, force=True)[source]¶
Set the value for the given list of keys
>>> sc.setnested(foo, ['a','b'], 3)
See sc.makenested() for full documentation.
- makenested(nesteddict, keylist=None, value=None, overwrite=False, generator=None)[source]¶
Little functions to get and set data from nested dictionaries.
The first two were adapted from: http://stackoverflow.com/questions/14692690/access-python-nested-dictionary-items-via-a-list-of-keys
“getnested” will get the value for the given list of keys:
>>> sc.getnested(foo, ['a','b'])
“setnested” will set the value for the given list of keys:
>>> sc.setnested(foo, ['a','b'], 3)
“makenested” will recursively update a dictionary with the given list of keys:
>>> sc.makenested(foo, ['a','b'])
“iternested” will return a list of all the twigs in the current dictionary:
>>> twigs = sc.iternested(foo)
Example 1:
foo = {} sc.makenested(foo, ['a','b']) foo['a']['b'] = 3 print(sc.getnested(foo, ['a','b'])) # 3 sc.setnested(foo, ['a','b'], 7) print(sc.getnested(foo, ['a','b'])) # 7 sc.makenested(foo, ['bar','cat']) sc.setnested(foo, ['bar','cat'], 'in the hat') print(foo['bar']) # {'cat': 'in the hat'}
Example 2:
foo = {} sc.makenested(foo, ['a','x']) sc.makenested(foo, ['a','y']) sc.makenested(foo, ['a','z']) sc.makenested(foo, ['b','a','x']) sc.makenested(foo, ['b','a','y']) count = 0 for twig in sc.iternested(foo): count += 1 sc.setnested(foo, twig, count) # {'a': {'y': 1, 'x': 2, 'z': 3}, 'b': {'a': {'y': 4, 'x': 5}}}
Version: 2014nov29
- iternested(nesteddict, previous=None)[source]¶
Return a list of all the twigs in the current dictionary
>>> twigs = sc.iternested(foo)
See sc.makenested() for full documentation.
- mergenested(dict1, dict2, die=False, verbose=False, _path=None)[source]¶
Merge different nested dictionaries
See sc.makenested() for full documentation.
Adapted from https://stackoverflow.com/questions/7204805/dictionaries-of-dictionaries-merge
- flattendict(nesteddict, sep=None, _prefix=None)[source]¶
Flatten nested dictionary
Example:
>>> sc.flattendict({'a':{'b':1,'c':{'d':2,'e':3}}}) {('a', 'b'): 1, ('a', 'c', 'd'): 2, ('a', 'c', 'e'): 3} >>> sc.flattendict({'a':{'b':1,'c':{'d':2,'e':3}}}, sep='_') {'a_b': 1, 'a_c_d': 2, 'a_c_e': 3}
- Parameters
d – Input dictionary potentially containing dicts as values
sep – Concatenate keys using string separator. If
None
the returned dictionary will have tuples as keys_prefix – Internal argument for recursively accumulating the nested keys
- Returns
A flat dictionary where no values are dicts
- search(obj, attribute, _trace='')[source]¶
Find a key or attribute within a dictionary or object.
This function facilitates finding nested key(s) or attributes within an object, by searching recursively through keys or attributes.
- Parameters
obj – A dict or class with __dict__ attribute
attribute – The substring to search for
_trace – Not for user input - internal variable used for recursion
- Returns
A list of matching attributes. The items in the list are the Python strings used to access the attribute (via attribute or dict indexing)
Example:
nested = {'a':{'foo':1, 'bar':2}, 'b':{'bar':3, 'cat':4}} matches = sc.search(nested, 'bar') # Returns ['["a"]["bar"]', '["b"]["bar"]']
- nestedloop(inputs, loop_order)[source]¶
Zip list of lists in order
This function takes in a list of lists to iterate over, and their nesting order. It then yields tuples of items in the given order. Only tested for two levels but in theory supports an arbitrary number of items.
- Parameters
inputs (list) – List of lists. All lists should have the same length
loop_order (list) – Nesting order for the lists
- Returns
Generator yielding tuples of items, one for each list
Example usage:
>>> list(sc.nestedloop([['a','b'],[1,2]],[0,1])) [['a', 1], ['a', 2], ['b', 1], ['b', 2]]
Notice how the first two items have the same value for the first list while the items from the second list vary. If the loop_order is reversed, then:
>>> list(sc.nestedloop([['a','b'],[1,2]],[1,0])) [['a', 1], ['b', 1], ['a', 2], ['b', 2]]
Notice now how now the first two items have different values from the first list but the same items from the second list.
From Atomica by Romesh Abeysuriya.
New in version 1.0.0.