"""Tools for working with lists."""
# --- import --------------------------------------------------------------------------------------
import itertools
# --- define --------------------------------------------------------------------------------------
__all__ = ["flatten_list", "intersperse", "get_index", "from_list_of_objects", "pairwise"]
# --- functions -----------------------------------------------------------------------------------
[docs]
def flatten_list(items, seqtypes=(list, tuple), in_place=True):
"""Flatten an irregular sequence.
Works generally but may be slower than it could
be if you can make assumptions about your list.
`Source`__
__ https://stackoverflow.com/a/10824086
Parameters
----------
items : iterable
The irregular sequence to flatten.
seqtypes : iterable of types (optional)
Types to flatten. Default is (list, tuple).
in_place : boolean (optional)
Toggle in_place flattening. Default is True.
Returns
-------
list
Flattened list.
Examples
--------
>>> l = [[[1, 2, 3], [4, 5]], 6]
>>> wt.kit.flatten_list(l)
[1, 2, 3, 4, 5, 6]
"""
if not in_place:
items = items[:]
for i, _ in enumerate(items):
while i < len(items) and isinstance(items[i], seqtypes):
items[i : i + 1] = items[i]
return items
[docs]
def intersperse(lis, value):
"""Put value between each existing item in list.
Parameters
----------
lis : list
List to intersperse.
value : object
Value to insert.
Returns
-------
list
interspersed list
"""
out = [value] * (len(lis) * 2 - 1)
out[0::2] = lis
return out
[docs]
def get_index(lis, argument):
"""Find the index of an item, given either the item or index as an argument.
Particularly useful as a wrapper for arguments like channel or axis.
Parameters
----------
lis : list
List to parse.
argument : int or object
Argument.
Returns
-------
int
Index of chosen object.
"""
# get channel
if isinstance(argument, int):
if -len(lis) <= argument < len(lis):
return argument
else:
raise IndexError("index {0} incompatible with length {1}".format(argument, len(lis)))
else:
return lis.index(argument)
def from_list_of_objects(values: list, attrs: list, hint):
"""
convenience wrapper of `get_index`.
Retrieve an object from a list of objects using either:
* its index,
* matching to an attr, or
* passing the value itself
the method normalizes a variety of input types to get the object itself.
arguments
---------
values: list
list of objects to be searched
attrs: list
list of attrs that correspond to objects in the list `values`
hint: str, list or object
if hint is a member of values, return the hint itself
returns
-------
match: desired_type
the member of `values` that matches the given hint.
Raises ValueError if a match is not found.
see also
--------
WrightTools.kit.get_index
"""
if isinstance(hint, int) or isinstance(hint, str):
return values[get_index(attrs, hint)]
elif hint in values:
return hint
else:
raise ValueError(f"could not find a member in values based on hint {hint}")
[docs]
def pairwise(iterable):
"""s -> (s0,s1), (s1,s2), (s2, s3), ...
Originally from `itertools docs`__
__ https://docs.python.org/3/library/itertools.html#itertools-recipes
Parameters
----------
iterable : iterable
Iterable from which to produce pairs
Returns
-------
generator
Generator which producis pairwise tuples
"""
a, b = itertools.tee(iterable)
next(b, None)
return zip(a, b)