Sequence

extepy.cycleperm(values, cycle)

Permutate a list according to cycle notation.

Parameters:

• values (list) – Sequence to permutate.

• cycle (list) – Permutation rule in cyclc notation.

Returns:

Permutated sequence.

Return type:

list

Examples

Permutate a list of strings.

>>> cycleperm(["a", "b", "c", "d", "e", "f", "g"], cycle=[1, 2, 4])
['a', 'c', 'e', 'd', 'b', 'f', 'g']

Permutate a list of integers.

>>> cycleperm(list(range(6)), cycle=[0, 1, 2])
[1, 2, 0, 3, 4, 5]

extepy.swap(values, i=0, j=1)

Swap two elements in a list.

Parameters:

• values (list) – Sequence to permutate.

• i (int) – Index of the first element to swap.

• j (int) – Index of the second element to swap.

Returns:

Swapped sequence.

Return type:

list

Examples

Swap two elements for a list of strings.

>>> swap(["a", "b", "c", "d", "e", "f", "g"], i=1, j=2)
['a', 'c', 'b', 'd', 'e', 'f', 'g']

Swap two elements for a list of integers.

>>> swap(list(range(6)), i=1, j=2)
[0, 2, 1, 3, 4, 5]

extepy.prioritize(values, index, dup='multiple')

Move some elements in the sequence to the beginning.

Parameters:

• values (list | tuple | str) – Sequence to permutate.

• index (int | list[int]) – Index of the elements to move to the beginning. The index can be negative. If there are duplicated index values, the same element will appear multiple times.

• dup ({"multiple", "unique", "raise"}) – Specify how to deal with the case that the same position is prioritized mutliple times. "multiple": The same element will appear multiple times. "unique": The same element will appear only once. "raise": Raise an error.

Return type:

list | tuple | str

Examples

Move a single positional argument to the beginning.

>>> prioritize(["a", "b", "c", "d"], index=-2)
['c', 'a', 'b', 'd']

Move multiple positional arguments to the beginning.

>>> prioritize(["a", "b", "c", "d"], index=[0, 2, -2])
['a', 'c', 'c', 'b', 'd']
>>> prioritize(["a", "b", "c", "d"], index=[0, 2, -2], dup="unique")
['a', 'c', 'b', 'd']