3b1b-manim/manimlib/utils/iterables.py
2020-02-07 09:30:47 -08:00

130 lines
3.3 KiB
Python

import itertools as it
import numpy as np
def remove_list_redundancies(l):
"""
Used instead of list(set(l)) to maintain order
Keeps the last occurance of each element
"""
reversed_result = []
used = set()
for x in reversed(l):
if x not in used:
reversed_result.append(x)
used.add(x)
reversed_result.reverse()
return reversed_result
def list_update(l1, l2):
"""
Used instead of list(set(l1).update(l2)) to maintain order,
making sure duplicates are removed from l1, not l2.
"""
return [e for e in l1 if e not in l2] + list(l2)
def list_difference_update(l1, l2):
return [e for e in l1 if e not in l2]
def all_elements_are_instances(iterable, Class):
return all([isinstance(e, Class) for e in iterable])
def adjacent_n_tuples(objects, n):
return zip(*[
[*objects[k:], *objects[:k]]
for k in range(n)
])
def adjacent_pairs(objects):
return adjacent_n_tuples(objects, 2)
def batch_by_property(items, property_func):
"""
Takes in a list, and returns a list of tuples, (batch, prop)
such that all items in a batch have the same output when
put into property_func, and such that chaining all these
batches together would give the original list (i.e. order is
preserved)
"""
batch_prop_pairs = []
def add_batch_prop_pair(batch):
if len(batch) > 0:
prop = property_func(batch[0])
batch_prop_pairs.append((batch, prop))
curr_batch = []
curr_prop = None
for item in items:
prop = property_func(item)
if prop != curr_prop:
add_batch_prop_pair(curr_batch)
curr_prop = prop
curr_batch = [item]
else:
curr_batch.append(item)
add_batch_prop_pair(curr_batch)
return batch_prop_pairs
def listify(obj):
if isinstance(obj, str):
return [obj]
try:
return list(obj)
except TypeError:
return [obj]
def stretch_array_to_length(nparray, length):
curr_len = len(nparray)
if curr_len > length:
raise Warning("Trying to stretch array to a length shorter than its own")
indices = np.arange(0, curr_len, curr_len / length).astype(int)
return nparray[indices]
def stretch_array_to_length_with_interpolation(nparray, length):
curr_len = len(nparray)
cont_indices = np.linspace(0, curr_len - 1, length)
return np.array([
(1 - a) * nparray[lh] + a * nparray[rh]
for ci in cont_indices
for lh, rh, a in [(int(ci), int(np.ceil(ci)), ci % 1)]
])
def make_even(iterable_1, iterable_2):
list_1 = list(iterable_1)
list_2 = list(iterable_2)
length = max(len(list_1), len(list_2))
return (
[list_1[(n * len(list_1)) // length] for n in range(length)],
[list_2[(n * len(list_2)) // length] for n in range(length)]
)
def make_even_by_cycling(iterable_1, iterable_2):
length = max(len(iterable_1), len(iterable_2))
cycle1 = it.cycle(iterable_1)
cycle2 = it.cycle(iterable_2)
return (
[next(cycle1) for x in range(length)],
[next(cycle2) for x in range(length)]
)
def remove_nones(sequence):
return [x for x in sequence if x]
# Note this is redundant with it.chain
def concatenate_lists(*list_of_lists):
return [item for l in list_of_lists for item in l]