File: //usr/lib/python2.7/dist-packages/cycler.py
from __future__ import (absolute_import, division, print_function,
unicode_literals)
import six
from itertools import product
from six.moves import zip, reduce
from operator import mul, add
import copy
__version__ = '0.9.0'
def _process_keys(left, right):
"""
Helper function to compose cycler keys
Parameters
----------
left, right : Cycler or None
The cyclers to be composed
Returns
-------
keys : set
The keys in the composition of the two cyclers
"""
l_key = left.keys if left is not None else set()
r_key = right.keys if right is not None else set()
if l_key & r_key:
raise ValueError("Can not compose overlapping cycles")
return l_key | r_key
class Cycler(object):
"""
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.
"""
def __init__(self, left, right=None, op=None):
"""Semi-private init
Do not use this directly, use `cycler` function instead.
"""
self._keys = _process_keys(left, right)
self._left = copy.copy(left)
self._right = copy.copy(right)
self._op = op
@property
def keys(self):
"""
The keys this Cycler knows about
"""
return set(self._keys)
def _compose(self):
"""
Compose the 'left' and 'right' components of this cycle
with the proper operation (zip or product as of now)
"""
for a, b in self._op(self._left, self._right):
out = dict()
out.update(a)
out.update(b)
yield out
@classmethod
def _from_iter(cls, label, itr):
"""
Class method to create 'base' Cycler objects
that do not have a 'right' or 'op' and for which
the 'left' object is not another Cycler.
Parameters
----------
label : str
The property key.
itr : iterable
Finite length iterable of the property values.
Returns
-------
cycler : Cycler
New 'base' `Cycler`
"""
ret = cls(None)
ret._left = list({label: v} for v in itr)
ret._keys = set([label])
return ret
def __getitem__(self, key):
# TODO : maybe add numpy style fancy slicing
if isinstance(key, slice):
trans = self._transpose()
return reduce(add, (cycler(k, v[key])
for k, v in six.iteritems(trans)))
else:
raise ValueError("Can only use slices with Cycler.__getitem__")
def __iter__(self):
if self._right is None:
return iter(self._left)
return self._compose()
def __add__(self, other):
"""
Pair-wise combine two equal length cycles (zip)
Parameters
----------
other : Cycler
The second Cycler
"""
if len(self) != len(other):
raise ValueError("Can only add equal length cycles, "
"not {0} and {1}".format(len(self), len(other)))
return Cycler(self, other, zip)
def __mul__(self, other):
"""
Outer product of two cycles (`itertools.product`) or integer
multiplication.
Parameters
----------
other : Cycler or int
The second Cycler or integer
"""
if isinstance(other, Cycler):
return Cycler(self, other, product)
elif isinstance(other, int):
trans = self._transpose()
return reduce(add, (cycler(k, v*other)
for k, v in six.iteritems(trans)))
else:
return NotImplemented
def __rmul__(self, other):
return self * other
def __len__(self):
op_dict = {zip: min, product: mul}
if self._right is None:
return len(self._left)
l_len = len(self._left)
r_len = len(self._right)
return op_dict[self._op](l_len, r_len)
def __iadd__(self, other):
"""
In-place pair-wise combine two equal length cycles (zip)
Parameters
----------
other : Cycler
The second Cycler
"""
old_self = copy.copy(self)
self._keys = _process_keys(old_self, other)
self._left = old_self
self._op = zip
self._right = copy.copy(other)
return self
def __imul__(self, other):
"""
In-place outer product of two cycles (`itertools.product`)
Parameters
----------
other : Cycler
The second Cycler
"""
old_self = copy.copy(self)
self._keys = _process_keys(old_self, other)
self._left = old_self
self._op = product
self._right = copy.copy(other)
return self
def __repr__(self):
op_map = {zip: '+', product: '*'}
if self._right is None:
lab = self.keys.pop()
itr = list(v[lab] for v in self)
return "cycler({lab!r}, {itr!r})".format(lab=lab, itr=itr)
else:
op = op_map.get(self._op, '?')
msg = "({left!r} {op} {right!r})"
return msg.format(left=self._left, op=op, right=self._right)
def _repr_html_(self):
# an table showing the value of each key through a full cycle
output = "<table>"
sorted_keys = sorted(self.keys)
for key in sorted_keys:
output += "<th>{key!r}</th>".format(key=key)
for d in iter(self):
output += "<tr>"
for k in sorted_keys:
output += "<td>{val!r}</td>".format(val=d[k])
output += "</tr>"
output += "</table>"
return output
def _transpose(self):
"""
Internal helper function which iterates through the
styles and returns a dict of lists instead of a list of
dicts. This is needed for multiplying by integers and
for __getitem__
Returns
-------
trans : dict
dict of lists for the styles
"""
# TODO : sort out if this is a bottle neck, if there is a better way
# and if we care.
keys = self.keys
# change this to dict comprehension when drop 2.6
out = dict((k, list()) for k in keys)
for d in self:
for k in keys:
out[k].append(d[k])
return out
def simplify(self):
"""Simplify the Cycler
Returned as a composition using only sums (no multiplications)
Returns
-------
simple : Cycler
An equivalent cycler using only summation"""
# TODO: sort out if it is worth the effort to make sure this is
# balanced. Currently it is is
# (((a + b) + c) + d) vs
# ((a + b) + (c + d))
# I would believe that there is some performance implications
trans = self._transpose()
return reduce(add, (cycler(k, v) for k, v in six.iteritems(trans)))
def cycler(label, itr):
"""
Create a new `Cycler` object from a property name and
iterable of values.
Parameters
----------
label : str
The property key.
itr : iterable
Finite length iterable of the property values.
Returns
-------
cycler : Cycler
New `Cycler` for the given property
"""
if isinstance(itr, Cycler):
keys = itr.keys
if len(keys) != 1:
msg = "Can not create Cycler from a multi-property Cycler"
raise ValueError(msg)
if label in keys:
return copy.copy(itr)
else:
lab = keys.pop()
itr = list(v[lab] for v in itr)
return Cycler._from_iter(label, itr)