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- import copy
- import operator
- from toolz.compatibility import (map, zip, iteritems, iterkeys, itervalues,
- reduce)
-
- __all__ = ('merge', 'merge_with', 'valmap', 'keymap', 'itemmap',
- 'valfilter', 'keyfilter', 'itemfilter',
- 'assoc', 'dissoc', 'assoc_in', 'update_in', 'get_in')
-
-
- def _get_factory(f, kwargs):
- factory = kwargs.pop('factory', dict)
- if kwargs:
- raise TypeError("{0}() got an unexpected keyword argument "
- "'{1}'".format(f.__name__, kwargs.popitem()[0]))
- return factory
-
-
- def merge(*dicts, **kwargs):
- """ Merge a collection of dictionaries
-
- >>> merge({1: 'one'}, {2: 'two'})
- {1: 'one', 2: 'two'}
-
- Later dictionaries have precedence
-
- >>> merge({1: 2, 3: 4}, {3: 3, 4: 4})
- {1: 2, 3: 3, 4: 4}
-
- See Also:
- merge_with
- """
- if len(dicts) == 1 and not isinstance(dicts[0], dict):
- dicts = dicts[0]
- factory = _get_factory(merge, kwargs)
-
- rv = factory()
- for d in dicts:
- rv.update(d)
- return rv
-
-
- def merge_with(func, *dicts, **kwargs):
- """ Merge dictionaries and apply function to combined values
-
- A key may occur in more than one dict, and all values mapped from the key
- will be passed to the function as a list, such as func([val1, val2, ...]).
-
- >>> merge_with(sum, {1: 1, 2: 2}, {1: 10, 2: 20})
- {1: 11, 2: 22}
-
- >>> merge_with(first, {1: 1, 2: 2}, {2: 20, 3: 30}) # doctest: +SKIP
- {1: 1, 2: 2, 3: 30}
-
- See Also:
- merge
- """
- if len(dicts) == 1 and not isinstance(dicts[0], dict):
- dicts = dicts[0]
- factory = _get_factory(merge_with, kwargs)
-
- result = factory()
- for d in dicts:
- for k, v in iteritems(d):
- if k not in result:
- result[k] = [v]
- else:
- result[k].append(v)
- return valmap(func, result, factory)
-
-
- def valmap(func, d, factory=dict):
- """ Apply function to values of dictionary
-
- >>> bills = {"Alice": [20, 15, 30], "Bob": [10, 35]}
- >>> valmap(sum, bills) # doctest: +SKIP
- {'Alice': 65, 'Bob': 45}
-
- See Also:
- keymap
- itemmap
- """
- rv = factory()
- rv.update(zip(iterkeys(d), map(func, itervalues(d))))
- return rv
-
-
- def keymap(func, d, factory=dict):
- """ Apply function to keys of dictionary
-
- >>> bills = {"Alice": [20, 15, 30], "Bob": [10, 35]}
- >>> keymap(str.lower, bills) # doctest: +SKIP
- {'alice': [20, 15, 30], 'bob': [10, 35]}
-
- See Also:
- valmap
- itemmap
- """
- rv = factory()
- rv.update(zip(map(func, iterkeys(d)), itervalues(d)))
- return rv
-
-
- def itemmap(func, d, factory=dict):
- """ Apply function to items of dictionary
-
- >>> accountids = {"Alice": 10, "Bob": 20}
- >>> itemmap(reversed, accountids) # doctest: +SKIP
- {10: "Alice", 20: "Bob"}
-
- See Also:
- keymap
- valmap
- """
- rv = factory()
- rv.update(map(func, iteritems(d)))
- return rv
-
-
- def valfilter(predicate, d, factory=dict):
- """ Filter items in dictionary by value
-
- >>> iseven = lambda x: x % 2 == 0
- >>> d = {1: 2, 2: 3, 3: 4, 4: 5}
- >>> valfilter(iseven, d)
- {1: 2, 3: 4}
-
- See Also:
- keyfilter
- itemfilter
- valmap
- """
- rv = factory()
- for k, v in iteritems(d):
- if predicate(v):
- rv[k] = v
- return rv
-
-
- def keyfilter(predicate, d, factory=dict):
- """ Filter items in dictionary by key
-
- >>> iseven = lambda x: x % 2 == 0
- >>> d = {1: 2, 2: 3, 3: 4, 4: 5}
- >>> keyfilter(iseven, d)
- {2: 3, 4: 5}
-
- See Also:
- valfilter
- itemfilter
- keymap
- """
- rv = factory()
- for k, v in iteritems(d):
- if predicate(k):
- rv[k] = v
- return rv
-
-
- def itemfilter(predicate, d, factory=dict):
- """ Filter items in dictionary by item
-
- >>> def isvalid(item):
- ... k, v = item
- ... return k % 2 == 0 and v < 4
-
- >>> d = {1: 2, 2: 3, 3: 4, 4: 5}
- >>> itemfilter(isvalid, d)
- {2: 3}
-
- See Also:
- keyfilter
- valfilter
- itemmap
- """
- rv = factory()
- for item in iteritems(d):
- if predicate(item):
- k, v = item
- rv[k] = v
- return rv
-
-
- def assoc(d, key, value, factory=dict):
- """ Return a new dict with new key value pair
-
- New dict has d[key] set to value. Does not modify the initial dictionary.
-
- >>> assoc({'x': 1}, 'x', 2)
- {'x': 2}
- >>> assoc({'x': 1}, 'y', 3) # doctest: +SKIP
- {'x': 1, 'y': 3}
- """
- d2 = factory()
- d2[key] = value
- return merge(d, d2, factory=factory)
-
-
- def dissoc(d, *keys):
- """ Return a new dict with the given key(s) removed.
-
- New dict has d[key] deleted for each supplied key.
- Does not modify the initial dictionary.
-
- >>> dissoc({'x': 1, 'y': 2}, 'y')
- {'x': 1}
- >>> dissoc({'x': 1, 'y': 2}, 'y', 'x')
- {}
- >>> dissoc({'x': 1}, 'y') # Ignores missing keys
- {'x': 1}
- """
- d2 = copy.copy(d)
- for key in keys:
- if key in d2:
- del d2[key]
- return d2
-
-
- def assoc_in(d, keys, value, factory=dict):
- """ Return a new dict with new, potentially nested, key value pair
-
- >>> purchase = {'name': 'Alice',
- ... 'order': {'items': ['Apple', 'Orange'],
- ... 'costs': [0.50, 1.25]},
- ... 'credit card': '5555-1234-1234-1234'}
- >>> assoc_in(purchase, ['order', 'costs'], [0.25, 1.00]) # doctest: +SKIP
- {'credit card': '5555-1234-1234-1234',
- 'name': 'Alice',
- 'order': {'costs': [0.25, 1.00], 'items': ['Apple', 'Orange']}}
- """
- return update_in(d, keys, lambda x: value, value, factory)
-
-
- def update_in(d, keys, func, default=None, factory=dict):
- """ Update value in a (potentially) nested dictionary
-
- inputs:
- d - dictionary on which to operate
- keys - list or tuple giving the location of the value to be changed in d
- func - function to operate on that value
-
- If keys == [k0,..,kX] and d[k0]..[kX] == v, update_in returns a copy of the
- original dictionary with v replaced by func(v), but does not mutate the
- original dictionary.
-
- If k0 is not a key in d, update_in creates nested dictionaries to the depth
- specified by the keys, with the innermost value set to func(default).
-
- >>> inc = lambda x: x + 1
- >>> update_in({'a': 0}, ['a'], inc)
- {'a': 1}
-
- >>> transaction = {'name': 'Alice',
- ... 'purchase': {'items': ['Apple', 'Orange'],
- ... 'costs': [0.50, 1.25]},
- ... 'credit card': '5555-1234-1234-1234'}
- >>> update_in(transaction, ['purchase', 'costs'], sum) # doctest: +SKIP
- {'credit card': '5555-1234-1234-1234',
- 'name': 'Alice',
- 'purchase': {'costs': 1.75, 'items': ['Apple', 'Orange']}}
-
- >>> # updating a value when k0 is not in d
- >>> update_in({}, [1, 2, 3], str, default="bar")
- {1: {2: {3: 'bar'}}}
- >>> update_in({1: 'foo'}, [2, 3, 4], inc, 0)
- {1: 'foo', 2: {3: {4: 1}}}
- """
- assert len(keys) > 0
- k, ks = keys[0], keys[1:]
- if ks:
- return assoc(d, k, update_in(d[k] if (k in d) else factory(),
- ks, func, default, factory),
- factory)
- else:
- innermost = func(d[k]) if (k in d) else func(default)
- return assoc(d, k, innermost, factory)
-
-
- def get_in(keys, coll, default=None, no_default=False):
- """ Returns coll[i0][i1]...[iX] where [i0, i1, ..., iX]==keys.
-
- If coll[i0][i1]...[iX] cannot be found, returns ``default``, unless
- ``no_default`` is specified, then it raises KeyError or IndexError.
-
- ``get_in`` is a generalization of ``operator.getitem`` for nested data
- structures such as dictionaries and lists.
-
- >>> transaction = {'name': 'Alice',
- ... 'purchase': {'items': ['Apple', 'Orange'],
- ... 'costs': [0.50, 1.25]},
- ... 'credit card': '5555-1234-1234-1234'}
- >>> get_in(['purchase', 'items', 0], transaction)
- 'Apple'
- >>> get_in(['name'], transaction)
- 'Alice'
- >>> get_in(['purchase', 'total'], transaction)
- >>> get_in(['purchase', 'items', 'apple'], transaction)
- >>> get_in(['purchase', 'items', 10], transaction)
- >>> get_in(['purchase', 'total'], transaction, 0)
- 0
- >>> get_in(['y'], {}, no_default=True)
- Traceback (most recent call last):
- ...
- KeyError: 'y'
-
- See Also:
- itertoolz.get
- operator.getitem
- """
- try:
- return reduce(operator.getitem, keys, coll)
- except (KeyError, IndexError, TypeError):
- if no_default:
- raise
- return default
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