cycler.Cycler

class cycler.Cycler(left: Cycler[K, V] | Iterable[dict[K, V]] | None, right: Cycler[K, V] | None = None, op: Any = None)

Composable cycles.

This class has compositions methods:

+

for ‘inner’ products (zip)

+=

in-place +

*

for outer products (itertools.product) and integer multiplication

*=

in-place *

and supports basic slicing via [].

Parameters:

left, rightCycler or None

The ‘left’ and ‘right’ cyclers.

opfunc or None

Function which composes the ‘left’ and ‘right’ cyclers.

__init__(left: Cycler[K, V] | Iterable[dict[K, V]] | None, right: Cycler[K, V] | None = None, op: Any = None)

Semi-private init.

Do not use this directly, use cycler function instead.

Methods

__init__(left[, right, op])	Semi-private init.
by_key()	Values by key.
change_key(old, new)	Change a key in this cycler to a new name.
concat(right)	Concatenate Cyclers, as if chained using itertools.chain.
simplify()	Simplify the cycler into a sum (but no products) of cyclers.

Attributes

keys	The keys this Cycler knows about.

by_key() → dict[K, list[V]]

Values by key.

This returns the transposed values of the cycler. Iterating over a Cycler yields dicts with a single value for each key, this method returns a dict of list which are the values for the given key.

The returned value can be used to create an equivalent Cycler using only +.

Returns:

transposedict

dict of lists of the values for each key.

change_key(old: K, new: K) → None

Change a key in this cycler to a new name. Modification is performed in-place.

Does nothing if the old key is the same as the new key. Raises a ValueError if the new key is already a key. Raises a KeyError if the old key isn’t a key.

concat(right: Cycler[K, U]) → Cycler[K, V | U]

Concatenate Cyclers, as if chained using itertools.chain.

The keys must match exactly.

Returns:

Cycler

The concatenated cycler.

Examples

>>> num = cycler('a', range(3))
>>> let = cycler('a', 'abc')
>>> num.concat(let)
cycler('a', [0, 1, 2, 'a', 'b', 'c'])

property keys: set[K]

The keys this Cycler knows about.

simplify() → Cycler[K, V]

Simplify the cycler into a sum (but no products) of cyclers.

Returns:

simpleCycler