lkj.iterables

Tools with iterables (dicts, lists, tuples, sets, etc.).

Functions

compare_sets(left, right)	Compares two iterables and returns a named tuple with:
get_by_value(list_of_dicts, value, field)	Get a dictionary from a list of dictionaries by a field value.
index_of(iterable, value)	List list.index but for any iterable.

Classes

SetsComparisonResult(common, left_only, ...)

class lkj.iterables.SetsComparisonResult(common, left_only, right_only)

Bases: NamedTuple

common: set

Alias for field number 0

left_only: set

Alias for field number 1

right_only: set

Alias for field number 2

lkj.iterables.compare_sets(left, right)

Compares two iterables and returns a named tuple with:

• Elements in both iterables.

• Elements only in the left iterable.

• Elements only in the right iterable.

Note

When applied to dicts, the comparison is done on the keys. If you want a comparison on the values, use compare_iterables(left.values(), right.values()).

Parameters:

• left (Iterable) – The first iterable.

• right (Iterable) – The second iterable.

Returns:

A namedtuple with fields common, left_only, and right_only.

Return type:

SetsComparisonResult

Examples

>>> left = ['a', 'b', 'c']
>>> right = ['b', 'c', 'd']
>>> result = compare_sets(left, right)
>>> assert result.common == {'b', 'c'}  # asserting because order is not guaranteed
>>> result.left_only
{'a'}
>>> result.right_only
{'d'}

lkj.iterables.get_by_value(list_of_dicts, value, field)

Get a dictionary from a list of dictionaries by a field value.

Return type:

Mapping[TypeVar(KT), TypeVar(VT)]

>>> data = [{'id': 1, 'value': 'A'}, {'id': 2, 'value': 'B'}]
>>> get_by_value(data, 2, 'id')
{'id': 2, 'value': 'B'}

This function just WANTS to be functools.partial-ized!!

>>> from functools import partial
>>> get_by_id = partial(get_by_value, field='id')
>>> get_by_id(data, 1)
{'id': 1, 'value': 'A'}
>>> get_value_of_B = partial(get_by_value, value='B', field='value')
>>> get_value_of_B(data)
{'id': 2, 'value': 'B'}

lkj.iterables.index_of(iterable, value)

List list.index but for any iterable.

Return type:

int

>>> index_of(iter('abc'), 'b')
1
>>> index_of(iter(range(5)), 3)
3
>>> index_of(iter('abc'), 'z')
Traceback (most recent call last):
...
ValueError: 'z' is not in iterable