cycler.Cycler

class cycler.Cycler(left, right=None, op=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 : Cycler or None

The ‘left’ cycler

right : Cycler or None

The ‘right’ cycler

op : func or None

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

__init__(left, right=None, op=None)

Semi-private init

Do not use this directly, use cycler function instead.

Methods

__init__(left[, right, op])	Semi-private init
change_key(old, new)	Change a key in this cycler to a new name.
concat(other)	Concatenate this cycler and an other.
simplify()	Simplify the Cycler

Attributes

keys	The keys this Cycler knows about

by_key()

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:

transpose : dict

dict of lists of the values for each key.

change_key(old, new)

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(other)

Concatenate this cycler and an other.

The keys must match exactly.

This returns a single Cycler which is equivalent to itertools.chain(self, other)

Parameters:

other : Cycler

The Cycler to concatenate to this one.

Returns:

ret : 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'])

keys

The keys this Cycler knows about

simplify()

Simplify the Cycler

Returned as a composition using only sums (no multiplications)

Returns:

simple : Cycler

An equivalent cycler using only summation