# -*- coding: utf-8 -*-
"""Functions that operate on lists and dicts.
.. versionadded:: 1.0.0
"""
from __future__ import absolute_import
import random
import pydash as pyd
from .helpers import itercallback, iterator, callit, getargcount, NoValue
from ._compat import cmp_to_key, _cmp
__all__ = (
'all_',
'any_',
'at',
'collect',
'contains',
'count_by',
'deep_pluck',
'detect',
'each',
'each_right',
'every',
'filter_',
'find',
'find_last',
'find_where',
'foldl',
'foldr',
'for_each',
'for_each_right',
'group_by',
'include',
'index_by',
'inject',
'invoke',
'map_',
'mapiter',
'max_',
'min_',
'partition',
'pluck',
'reduce_',
'reduce_right',
'reductions',
'reductions_right',
'reject',
'sample',
'select',
'shuffle',
'size',
'some',
'sort_by',
'sort_by_all',
'sort_by_order',
'to_list',
'where',
)
[docs]def at(collection, *indexes): # pylint: disable=invalid-name
"""Creates a list of elements from the specified indexes, or keys, of the
collection. Indexes may be specified as individual arguments or as arrays
of indexes.
Args:
collection (list|dict): Collection to iterate over.
indexes (mixed): The indexes of `collection` to retrieve, specified as
individual indexes or arrays of indexes.
Returns:
list: filtered list
Example:
>>> at([1, 2, 3, 4], 0, 2)
[1, 3]
>>> at({'a': 1, 'b': 2, 'c': 3, 'd': 4}, 'a', 'c')
[1, 3]
.. versionadded:: 1.0.0
"""
indexes = pyd.flatten_deep(indexes)
return [collection[i] for i in indexes]
[docs]def contains(collection, target, from_index=0):
"""Checks if a given value is present in a collection. If `from_index` is
negative, it is used as the offset from the end of the collection.
Args:
collection (list|dict): Collection to iterate over.
target (mixed): Target value to compare to.
from_index (int, optional): Offset to start search from.
Returns:
bool: Whether `target` is in `collection`.
Example:
>>> contains([1, 2, 3, 4], 2)
True
>>> contains([1, 2, 3, 4], 2, from_index=2)
False
>>> contains({'a': 1, 'b': 2, 'c': 3, 'd': 4}, 2)
True
See Also:
- :func:`contains` (main definition)
- :func:`include` (alias)
.. versionadded:: 1.0.0
"""
if isinstance(collection, dict):
collection = collection.values()
else:
# only makes sense to do this if `collection` is not a dict
collection = collection[from_index:]
return target in collection
include = contains
[docs]def count_by(collection, callback=None):
"""Creates an object composed of keys generated from the results of running
each element of `collection` through the callback.
Args:
collection (list|dict): Collection to iterate over.
callback (mixed, optional): Callback applied per iteration.
Returns:
dict: Dict containing counts by key.
Example:
>>> results = count_by([1, 2, 1, 2, 3, 4])
>>> assert results == {1: 2, 2: 2, 3: 1, 4: 1}
>>> results = count_by(['a', 'A', 'B', 'b'], lambda x: x.lower())
>>> assert results == {'a': 2, 'b': 2}
>>> results = count_by({'a': 1, 'b': 1, 'c': 3, 'd': 3})
>>> assert results == {1: 2, 3: 2}
.. versionadded:: 1.0.0
"""
ret = {}
for result in itercallback(collection, callback):
ret.setdefault(result[0], 0)
ret[result[0]] += 1
return ret
[docs]def deep_pluck(collection, path):
"""Like pluck but works with deep paths.
Args:
collection (list|dict): list of dicts
path (str|list): collection's path to pluck
Returns:
list: plucked list
Example:
>>> deep_pluck([[[0, 1]], [[2, 3]], [[4, 5]]], '0.1')
[1, 3, 5]
>>> deep_pluck([{'a': {'b': 1}}, {'a': {'b': 2}}], 'a.b')
[1, 2]
>>> deep_pluck([{'a': {'b': [0, 1]}}, {'a': {'b': [2, 3]}}], 'a.b.1')
[1, 3]
.. versionadded:: 2.2.0
"""
return map_(collection, pyd.deep_property(path))
[docs]def every(collection, callback=None):
"""Checks if the callback returns a truthy value for all elements of a
collection. The callback is invoked with three arguments:
``(value, index|key, collection)``. If a property name is passed for
callback, the created :func:`pluck` style callback will return the property
value of the given element. If an object is passed for callback, the
created :func:`where` style callback will return ``True`` for elements that
have the properties of the given object, else ``False``.
Args:
collection (list|dict): Collection to iterate over.
callback (mixed, optional): Callback applied per iteration.
Returns:
bool: Whether all elements are truthy.
Example:
>>> every([1, True, 'hello'])
True
>>> every([1, False, 'hello'])
False
>>> every([{'a': 1}, {'a': True}, {'a': 'hello'}], 'a')
True
>>> every([{'a': 1}, {'a': False}, {'a': 'hello'}], 'a')
False
>>> every([{'a': 1}, {'a': 1}], {'a': 1})
True
>>> every([{'a': 1}, {'a': 2}], {'a': 1})
False
See Also:
- :func:`every` (main definition)
- :func:`all_` (alias)
.. versionadded:: 1.0.0
"""
if callback:
cbk = pyd.iteratee(callback)
collection = [cbk(item) for item in collection]
return all(collection)
all_ = every
[docs]def filter_(collection, callback=None):
"""Iterates over elements of a collection, returning a list of all elements
the callback returns truthy for.
Args:
collection (list|dict): Collection to iterate over.
callback (mixed, optional): Callback applied per iteration.
Returns:
list: Filtered list.
Example:
>>> results = filter_([{'a': 1}, {'b': 2}, {'a': 1, 'b': 3}], {'a': 1})
>>> assert results == [{'a': 1}, {'a': 1, 'b': 3}]
>>> filter_([1, 2, 3, 4], lambda x: x >= 3)
[3, 4]
See Also:
- :func:`select` (main definition)
- :func:`filter_` (alias)
.. versionadded:: 1.0.0
"""
return [value
for is_true, value, _, _ in itercallback(collection, callback)
if is_true]
select = filter_
[docs]def find(collection, callback=None):
"""Iterates over elements of a collection, returning the first element that
the callback returns truthy for.
Args:
collection (list|dict): Collection to iterate over.
callback (mixed, optional): Callback applied per iteration.
Returns:
mixed: First element found or ``None``.
Example:
>>> find([1, 2, 3, 4], lambda x: x >= 3)
3
>>> find([{'a': 1}, {'b': 2}, {'a': 1, 'b': 2}], {'a': 1})
{'a': 1}
See Also:
- :func:`find` (main definition)
- :func:`detect` (alias)
- :func:`find_where` (alias)
.. versionadded:: 1.0.0
"""
search = (collection[key]
for is_true, _, key, _ in itercallback(collection, callback)
if is_true)
return next(search, None)
detect = find
find_where = find
[docs]def find_last(collection, callback=None):
"""This method is like :func:`find` except that it iterates over elements
of a `collection` from right to left.
Args:
collection (list|dict): Collection to iterate over.
callback (mixed, optional): Callback applied per iteration.
Returns:
mixed: Last element found or ``None``.
Example:
>>> find_last([1, 2, 3, 4], lambda x: x >= 3)
4
>>> results = find_last([{'a': 1}, {'b': 2}, {'a': 1, 'b': 2}],\
{'a': 1})
>>> assert results == {'a': 1, 'b': 2}
.. versionadded:: 1.0.0
"""
search = (collection[key]
for is_true, _, key, _ in itercallback(collection,
callback,
reverse=True)
if is_true)
return next(search, None)
[docs]def for_each(collection, callback=None):
"""Iterates over elements of a collection, executing the callback for each
element.
Args:
collection (list|dict): Collection to iterate over.
callback (mixed, optional): Callback applied per iteration.
Returns:
list|dict: `collection`
Example:
>>> results = {}
>>> def cb(x): results[x] = x ** 2
>>> each([1, 2, 3, 4], cb)
[1, 2, 3, 4]
>>> assert results == {1: 1, 2: 4, 3: 9, 4: 16}
See Also:
- :func:`for_each` (main definition)
- :func:`each` (alias)
.. versionadded:: 1.0.0
"""
next((None for ret, _, _, _ in itercallback(collection, callback)
if ret is False),
None)
return collection
each = for_each
[docs]def for_each_right(collection, callback):
"""This method is like :func:`for_each` except that it iterates over
elements of a `collection` from right to left.
Args:
collection (list|dict): Collection to iterate over.
callback (mixed, optional): Callback applied per iteration.
Returns:
list|dict: `collection`
Example:
>>> results = {'total': 1}
>>> def cb(x): results['total'] = x * results['total']
>>> each_right([1, 2, 3, 4], cb)
[1, 2, 3, 4]
>>> assert results == {'total': 24}
See Also:
- :func:`for_each_right` (main definition)
- :func:`each_right` (alias)
.. versionadded:: 1.0.0
"""
next((None for ret, _, _, _ in itercallback(collection,
callback,
reverse=True)
if ret is False),
None)
return collection
each_right = for_each_right
[docs]def group_by(collection, callback=None):
"""Creates an object composed of keys generated from the results of running
each element of a `collection` through the callback.
Args:
collection (list|dict): Collection to iterate over.
callback (mixed, optional): Callback applied per iteration.
Returns:
dict: Results of grouping by `callback`.
Example:
>>> results = group_by([{'a': 1, 'b': 2}, {'a': 3, 'b': 4}], 'a')
>>> assert results == {1: [{'a': 1, 'b': 2}], 3: [{'a': 3, 'b': 4}]}
>>> results = group_by([{'a': 1, 'b': 2}, {'a': 3, 'b': 4}], {'a': 1})
>>> assert results == {False: [{'a': 3, 'b': 4}],\
True: [{'a': 1, 'b': 2}]}
.. versionadded:: 1.0.0
"""
ret = {}
cbk = pyd.iteratee(callback)
for value in collection:
key = cbk(value)
ret.setdefault(key, [])
ret[key].append(value)
return ret
[docs]def index_by(collection, callback=None):
"""Creates an object composed of keys generated from the results of running
each element of the collection through the given callback.
Args:
collection (list|dict): Collection to iterate over.
callback (mixed, optional): Callback applied per iteration.
Returns:
dict: Results of indexing by `callback`.
Example:
>>> results = index_by([{'a': 1, 'b': 2}, {'a': 3, 'b': 4}], 'a')
>>> assert results == {1: {'a': 1, 'b': 2}, 3: {'a': 3, 'b': 4}}
.. versionadded:: 1.0.0
"""
ret = {}
cbk = pyd.iteratee(callback)
for value in collection:
ret[cbk(value)] = value
return ret
[docs]def invoke(collection, method_name, *args, **kargs):
"""Invokes the method named by `method_name` on each element in the
`collection` returning a list of the results of each invoked method.
Args:
collection (list|dict): Collection to iterate over.
method_name (str): Name of method to invoke.
args (optional): Arguments to pass to method call.
kargs (optional): Keyword arguments to pass to method call.
Returns:
list: List of results of invoking method of each item.
Example:
>>> items = [[1, 2], [2, 3], [3, 4]]
>>> invoke(items, 'pop')
[2, 3, 4]
>>> items
[[1], [2], [3]]
>>> items = [[1, 2], [2, 3], [3, 4]]
>>> invoke(items, 'pop', 0)
[1, 2, 3]
>>> items
[[2], [3], [4]]
.. versionadded:: 1.0.0
"""
lst = []
for item in collection:
if callable(method_name):
lst.append(method_name(item, *args, **kargs))
else:
lst.append(getattr(item, method_name)(*args, **kargs))
return lst
[docs]def map_(collection, callback=None):
"""Creates an array of values by running each element in the collection
through the callback. The callback is invoked with three arguments:
``(value, index|key, collection)``. If a property name is passed for
callback, the created :func:`pluck` style callback will return the property
value of the given element. If an object is passed for callback, the
created :func:`where` style callback will return ``True`` for elements that
have the properties of the given object, else ``False``.
Args:
collection (list|dict): Collection to iterate over.
callback (mixed, optional): Callback applied per iteration.
Returns:
list: Mapped list.
Example:
>>> map_([1, 2, 3, 4], str)
['1', '2', '3', '4']
See Also:
- :func:`map_` (main definition)
- :func:`collect` (alias)
.. versionadded:: 1.0.0
"""
return list(mapiter(collection, callback))
collect = map_
[docs]def mapiter(collection, callback=None):
"""Like :func:`map_` except returns a generator.
Args:
collection (list|dict): Collection to iterate over.
callback (mixed, optional): Callback applied per iteration.
Returns:
generator: Each mapped item.
Example:
>>> gen = mapiter([1, 2, 3, 4], str)
>>> next(gen)
'1'
>>> next(gen)
'2'
>>> list(gen)
['3', '4']
.. versionadded:: 2.1.0
"""
for result in itercallback(collection, callback):
yield result[0]
class _iterator_with_default(object):
def __init__(self, collection, default):
self.iter = iter(collection)
self.default = default
def __iter__(self):
return self
def next_default(self):
ret = self.default
self.default = NoValue
return ret
def __next__(self):
ret = next(self.iter, self.next_default())
if ret is NoValue:
raise StopIteration
return ret
next = __next__
[docs]def max_(collection, callback=None, default=NoValue):
"""Retrieves the maximum value of a `collection`.
Args:
collection (list|dict): Collection to iterate over.
callback (mixed, optional): Callback applied per iteration.
default: default value when collection is empty
Returns:
mixed: Maximum value.
Example:
>>> max_([1, 2, 3, 4])
4
>>> max_([{'a': 1}, {'a': 2}, {'a': 3}], 'a')
{'a': 3}
>>> max_([], default=-1)
-1
.. versionadded:: 1.0.0
"""
if isinstance(collection, dict):
collection = collection.values()
return max(_iterator_with_default(collection, default),
key=pyd.iteratee(callback))
[docs]def min_(collection, callback=None, default=NoValue):
"""Retrieves the minimum value of a `collection`.
Args:
collection (list|dict): Collection to iterate over.
callback (mixed, optional): Callback applied per iteration.
Returns:
mixed: Minimum value.
Example:
>>> min_([1, 2, 3, 4])
1
>>> min_([{'a': 1}, {'a': 2}, {'a': 3}], 'a')
{'a': 1}
>>> min_([], default=100)
100
.. versionadded:: 1.0.0
"""
if isinstance(collection, dict):
collection = collection.values()
return min(_iterator_with_default(collection, default),
key=pyd.iteratee(callback))
[docs]def partition(collection, callback=None):
"""Creates an array of elements split into two groups, the first of which
contains elements the `callback` returns truthy for, while the second of
which contains elements the `callback` returns falsey for. The `callback`
is invoked with three arguments: ``(value, index|key, collection)``.
If a property name is provided for `callback` the created :func:`pluck`
style callback returns the property value of the given element.
If an object is provided for `callback` the created :func:`where` style
callback returns ``True`` for elements that have the properties of the
given object, else ``False``.
Args:
collection (list|dict): Collection to iterate over.
callback (mixed, optional): Callback applied per iteration.
Returns:
list: List of grouped elements.
Example:
>>> partition([1, 2, 3, 4], lambda x: x >= 3)
[[3, 4], [1, 2]]
.. versionadded:: 1.1.0
"""
trues = []
falses = []
for is_true, value, _, _ in itercallback(collection, callback):
if is_true:
trues.append(value)
else:
falses.append(value)
return [trues, falses]
[docs]def pluck(collection, key):
"""Retrieves the value of a specified property from all elements in the
collection.
Args:
collection (list): List of dicts.
key (str): Collection's key to pluck.
Returns:
list: Plucked list.
Example:
>>> pluck([{'a': 1, 'b': 2}, {'a': 3, 'b': 4}, {'a': 5, 'b': 6}], 'a')
[1, 3, 5]
.. versionadded:: 1.0.0
"""
return map_(collection, pyd.prop(key))
[docs]def reduce_(collection, callback=None, accumulator=None):
"""Reduces a collection to a value which is the accumulated result of
running each element in the collection through the callback, where each
successive callback execution consumes the return value of the previous
execution.
Args:
collection (list|dict): Collection to iterate over.
callback (mixed): Callback applied per iteration.
accumulator (mixed, optional): Initial value of aggregator. Default is
to use the result of the first iteration.
Returns:
mixed: Accumulator object containing results of reduction.
Example:
>>> reduce_([1, 2, 3, 4], lambda total, x: total * x)
24
See Also:
- :func:`reduce_` (main definition)
- :func:`foldl` (alias)
- :func:`inject` (alias)
.. versionadded:: 1.0.0
"""
iterable = iterator(collection)
if accumulator is None:
try:
_, accumulator = next(iterable)
except StopIteration:
raise TypeError(
'reduce_() of empty sequence with no initial value')
result = accumulator
if callback is None:
callback = pyd.identity
argcount = getargcount(callback, maxargs=3)
for index, item in iterable:
result = callit(callback, result, item, index, argcount=argcount)
return result
foldl = reduce_
inject = reduce_
[docs]def reduce_right(collection, callback=None, accumulator=None):
"""This method is like :func:`reduce_` except that it iterates over
elements of a `collection` from right to left.
Args:
collection (list|dict): Collection to iterate over.
callback (mixed): Callback applied per iteration.
accumulator (mixed, optional): Initial value of aggregator. Default is
to use the result of the first iteration.
Returns:
mixed: Accumulator object containing results of reduction.
Example:
>>> reduce_right([1, 2, 3, 4], lambda total, x: total ** x)
4096
See Also:
- :func:`reduce_right` (main definition)
- :func:`foldr` (alias)
.. versionadded:: 1.0.0
.. versionchanged:: 3.2.1
Fix bug where collection was not reversed correctly.
"""
if not isinstance(collection, dict):
collection = list(collection)[::-1]
return reduce_(collection, callback, accumulator)
foldr = reduce_right
[docs]def reductions(collection, callback=None, accumulator=None, from_right=False):
"""This function is like :func:`reduce_` except that it returns a list of
every intermediate value in the reduction operation.
Args:
collection (list|dict): Collection to iterate over.
callback (mixed): Callback applied per iteration.
accumulator (mixed, optional): Initial value of aggregator. Default is
to use the result of the first iteration.
Returns:
list: Results of each reduction operation.
Example:
>>> reductions([1, 2, 3, 4], lambda total, x: total * x)
[2, 6, 24]
Note:
The last element of the returned list would be the result of using
:func:`reduce_`.
.. versionadded:: 2.0.0
"""
if callback is None:
callback = pyd.identity
results = []
argcount = getargcount(callback, maxargs=3)
def interceptor(result, item, index): # pylint: disable=missing-docstring
result = callit(callback, result, item, index, argcount=argcount)
results.append(result)
return result
reducer = reduce_right if from_right else reduce_
reducer(collection, interceptor, accumulator)
return results
[docs]def reductions_right(collection, callback=None, accumulator=None):
"""This method is like :func:`reductions` except that it iterates over
elements of a `collection` from right to left.
Args:
collection (list|dict): Collection to iterate over.
callback (mixed): Callback applied per iteration.
accumulator (mixed, optional): Initial value of aggregator. Default is
to use the result of the first iteration.
Returns:
list: Results of each reduction operation.
Example:
>>> reductions_right([1, 2, 3, 4], lambda total, x: total ** x)
[64, 4096, 4096]
Note:
The last element of the returned list would be the result of using
:func:`reduce_`.
.. versionadded:: 2.0.0
"""
return reductions(collection, callback, accumulator, from_right=True)
[docs]def reject(collection, callback=None):
"""The opposite of :func:`filter_` this method returns the elements of a
collection that the callback does **not** return truthy for.
Args:
collection (list|dict): Collection to iterate over.
callback (mixed, optional): Callback applied per iteration.
Returns:
list: Rejected elements of `collection`.
Example:
>>> reject([1, 2, 3, 4], lambda x: x >= 3)
[1, 2]
>>> reject([{'a': 0}, {'a': 1}, {'a': 2}], 'a')
[{'a': 0}]
>>> reject([{'a': 0}, {'a': 1}, {'a': 2}], {'a': 1})
[{'a': 0}, {'a': 2}]
.. versionadded:: 1.0.0
"""
return [value
for is_true, value, _, _ in itercallback(collection, callback)
if not is_true]
[docs]def sample(collection, n=None):
"""Retrieves a random element or `n` random elements from a `collection`.
Args:
collection (list|dict): Collection to iterate over.
n (int, optional): Number of random samples to return.
Returns:
list|mixed: List of sampled collection value if `n` is provided, else
single value from collection if `n` is ``None``.
Example:
>>> items = [1, 2, 3, 4, 5]
>>> results = sample(items, 2)
>>> assert len(results) == 2
>>> assert set(items).intersection(results) == set(results)
.. versionadded:: 1.0.0
"""
num = min(n or 1, len(collection))
sampled = random.sample(collection, num)
return sampled[0] if n is None else sampled
[docs]def shuffle(collection):
"""Creates a list of shuffled values, using a version of the Fisher-Yates
shuffle.
Args:
collection (list|dict): Collection to iterate over.
Returns:
list: Shuffled list of values.
Example:
>>> items = [1, 2, 3, 4]
>>> results = shuffle(items)
>>> assert len(results) == len(items)
>>> assert set(results) == set(items)
.. versionadded:: 1.0.0
"""
if isinstance(collection, dict):
collection = collection.values()
# Make copy of collection since random.shuffle works on list in-place.
collection = list(collection)
# NOTE: random.shuffle uses Fisher-Yates.
random.shuffle(collection)
return collection
[docs]def size(collection):
"""Gets the size of the `collection` by returning `len(collection)` for
iterable objects.
Args:
collection (list|dict): Collection to iterate over.
Returns:
int: Collection length.
Example:
>>> size([1, 2, 3, 4])
4
.. versionadded:: 1.0.0
"""
return len(collection)
[docs]def some(collection, callback=None):
"""Checks if the callback returns a truthy value for any element of a
collection. The callback is invoked with three arguments:
``(value, index|key, collection)``. If a property name is passed for
callback, the created :func:`pluck` style callback will return the property
value of the given element. If an object is passed for callback, the
created :func:`where` style callback will return ``True`` for elements that
have the properties of the given object, else ``False``.
Args:
collection (list|dict): Collection to iterate over.
callbacked (mixed, optional): Callback applied per iteration.
Returns:
bool: Whether any of the elements are truthy.
Example:
>>> some([False, True, 0])
True
>>> some([False, 0, None])
False
>>> some([1, 2, 3, 4], lambda x: x >= 3)
True
>>> some([1, 2, 3, 4], lambda x: x == 0)
False
See Also:
- :func:`some` (main definition)
- :func:`any_` (alias)
.. versionadded:: 1.0.0
"""
if callback:
cbk = pyd.iteratee(callback)
collection = [cbk(item) for item in collection]
return any(collection)
any_ = some
[docs]def sort_by(collection, callback=None, reverse=False):
"""Creates a list of elements, sorted in ascending order by the results of
running each element in a `collection` through the callback.
Args:
collection (list|dict): Collection to iterate over.
callback (mixed, optional): Callback applied per iteration.
reverse (bool, optional): Whether to reverse the sort. Defaults to
``False``.
Returns:
list: Sorted list.
Example:
>>> sort_by({'a': 2, 'b': 3, 'c': 1})
[1, 2, 3]
>>> sort_by({'a': 2, 'b': 3, 'c': 1}, reverse=True)
[3, 2, 1]
>>> sort_by([{'a': 2}, {'a': 3}, {'a': 1}], 'a')
[{'a': 1}, {'a': 2}, {'a': 3}]
.. versionadded:: 1.0.0
"""
if isinstance(collection, dict):
collection = collection.values()
return sorted(collection, key=pyd.iteratee(callback), reverse=reverse)
[docs]def sort_by_all(collection, keys, orders=None, reverse=False):
"""This method is like :func:`sort_by` except that it sorts by key names
instead of an iteratee function. Keys can be sorted in descending order by
prepending a ``"-"`` to the key name (e.g. ``"name"`` would become
``"-name"``) or by passing a list of boolean sort options via `orders`
where ``True`` is ascending and ``False`` is descending.
Args:
collection (list|dict): Collection to iterate over.
keys (list): List of keys to sort by. By default, keys will be sorted
in ascending order. To sort a key in descending order, prepend a
``"-"`` to the key name. For example, to sort the key value for
``"name"`` in descending order, use ``"-name"``.
orders (list, optional): List of boolean sort orders to apply for each
key. ``True`` corresponds to ascending order while ``False`` is
descending. Defaults to ``None``.
reverse (bool, optional): Whether to reverse the sort. Defaults to
``False``.
Returns:
list: Sorted list.
Example:
>>> items = [{'a': 2, 'b': 1}, {'a': 3, 'b': 2}, {'a': 1, 'b': 3}]
>>> results = sort_by_all(items, ['b', 'a'])
>>> assert results == [{'a': 2, 'b': 1},\
{'a': 3, 'b': 2},\
{'a': 1, 'b': 3}]
>>> results = sort_by_all(items, ['a', 'b'])
>>> assert results == [{'a': 1, 'b': 3},\
{'a': 2, 'b': 1},\
{'a': 3, 'b': 2}]
>>> results = sort_by_all(items, ['-a', 'b'])
>>> assert results == [{'a': 3, 'b': 2},\
{'a': 2, 'b': 1},\
{'a': 1, 'b': 3}]
>>> results = sort_by_all(items, ['a', 'b'], [False, True])
>>> assert results == [{'a': 3, 'b': 2},\
{'a': 2, 'b': 1},\
{'a': 1, 'b': 3}]
See Also:
- :func:`sort_by_all` (main definition)
- :func:`sort_by_order` (alias)
.. versionadded:: 3.0.0
.. versionchanged:: 3.2.0
Added `orders` argument.
.. versionchanged:: 3.2.0
Added :func:`sort_by_order` as alias.
"""
if isinstance(collection, dict):
collection = collection.values()
# Maintain backwards compatibility.
if pyd.is_bool(orders):
reverse = orders
orders = None
comparers = []
if orders:
for i, key in enumerate(keys):
if pyd.has(orders, i):
order = 1 if orders[i] else -1
else:
order = 1
comparers.append((pyd.deep_prop(key), order))
else:
for key in keys:
if key.startswith('-'):
order = -1
key = key[1:]
else:
order = 1
comparers.append((pyd.deep_prop(key), order))
def comparison(left, right):
# pylint: disable=useless-else-on-loop,missing-docstring
for func, mult in comparers:
result = _cmp(func(left), func(right))
if result:
return mult * result
else:
return 0
return sorted(collection, key=cmp_to_key(comparison), reverse=reverse)
sort_by_order = sort_by_all
[docs]def to_list(collection):
"""Converts the collection to a list.
Args:
collection (list|dict): Collection to iterate over.
Returns:
list: Collection converted to list.
Example:
>>> results = to_list({'a': 1, 'b': 2, 'c': 3})
>>> assert set(results) == set([1, 2, 3])
>>> to_list((1, 2, 3, 4))
[1, 2, 3, 4]
.. versionadded:: 1.0.0
"""
if isinstance(collection, dict):
ret = collection.values()
else:
ret = list(collection)
return ret
[docs]def where(collection, properties):
"""Examines each element in a collection, returning an array of all
elements that have the given properties.
Args:
collection (list|dict): Collection to iterate over.
properties (dict): property values to filter by
Returns:
list: filtered list.
Example:
>>> results = where([{'a': 1}, {'b': 2}, {'a': 1, 'b': 3}], {'a': 1})
>>> assert results == [{'a': 1}, {'a': 1, 'b': 3}]
.. versionadded:: 1.0.0
"""
return filter_(collection, pyd.matches(properties))