kopia lustrzana https://github.com/micropython/micropython-lib
updates:4 additions: 13 tests
updated: accumulate, chain, islice, tee; added: chain.from_iterable, combinations, combinations_with_replacement,compress, dropwhile, filterfalse, groupby, pairwise, permutations, product,takewhile, zip_longest; also added tests for all functionspull/581/head
rkompass
rodzic
0051a5ef50
commit
8698e33a77
|
|
@ -1,74 +1,317 @@
|
|||
# Python itertools adapted for Micropython by rkompass (2022)
|
||||
# Largely, but not exclusively based on code from the offical Python documentation
|
||||
# (https://docs.python.org/3/library/itertools.html)
|
||||
# Copyright 2001-2019 Python Software Foundation; All Rights Reserved
|
||||
|
||||
# consumes about 5kB if imported
|
||||
|
||||
# accumulate([1,2,3,4,5]) --> 1 3 6 10 15
|
||||
# accumulate([1,2,3,4,5], initial=100) --> 100 101 103 106 110 115
|
||||
# accumulate([1,2,3,4,5], lambda x, y: x * y) --> 1 2 6 24 120
|
||||
def accumulate(iterable, func=lambda x, y: x + y, initial=None):
|
||||
it = iter(iterable)
|
||||
total = initial
|
||||
if initial is None:
|
||||
try:
|
||||
total = next(it)
|
||||
except StopIteration:
|
||||
return
|
||||
yield total
|
||||
for element in it:
|
||||
total = func(total, element)
|
||||
yield total
|
||||
|
||||
# chain('abcd',[],range(5))) --> 'a' 'b' 'c' 'd' 0 1 2 3 4
|
||||
class chain:
|
||||
def __init__(self, *iterables):
|
||||
self.iterables = list(iterables)
|
||||
self.it = iter([])
|
||||
def __iter__(self):
|
||||
return self
|
||||
def __next__(self):
|
||||
while True:
|
||||
try:
|
||||
return next(self.it)
|
||||
except StopIteration:
|
||||
try:
|
||||
self.it = iter(self.iterables.pop(0))
|
||||
continue
|
||||
except IndexError:
|
||||
raise StopIteration
|
||||
# chain.from_iterable(['ABC', 'DEF']) --> 'A' 'B' 'C' 'D' 'E' 'F'
|
||||
@staticmethod
|
||||
def from_iterable(iterables):
|
||||
for it in iterables:
|
||||
yield from it
|
||||
|
||||
# combinations('ABCD', 2) --> ('A','B') ('A','C') ('A','D') ('B','C') ('B','D') ('C','D')
|
||||
def combinations(iterable, r):
|
||||
pool = tuple(iterable)
|
||||
n = len(pool)
|
||||
if r > n:
|
||||
return
|
||||
indices = list(range(r))
|
||||
yield tuple(pool[i] for i in indices)
|
||||
while True:
|
||||
index = 0
|
||||
for i in reversed(range(r)):
|
||||
if indices[i] != i + n - r:
|
||||
index = i
|
||||
break
|
||||
else:
|
||||
return
|
||||
indices[index] += 1
|
||||
for j in range(index + 1, r):
|
||||
indices[j] = indices[j - 1] + 1
|
||||
yield tuple(pool[i] for i in indices)
|
||||
|
||||
# combinations_with_replacement('ABC', 2) --> ('A','A') ('A','B') ('A','C') ('B','B') ('B','C') ('C','C')
|
||||
def combinations_with_replacement(iterable, r):
|
||||
pool = tuple(iterable)
|
||||
n = len(pool)
|
||||
if not n and r:
|
||||
return
|
||||
indices = [0] * r
|
||||
yield tuple(pool[i] for i in indices)
|
||||
while True:
|
||||
index = 0
|
||||
for i in reversed(range(r)):
|
||||
if indices[i] != n - 1:
|
||||
index = i
|
||||
break
|
||||
else:
|
||||
return
|
||||
indices[index:] = [indices[index] + 1] * (r - index)
|
||||
yield tuple(pool[i] for i in indices)
|
||||
|
||||
# compress('ABCDEF', [1,0,1,0,1,1]) --> A C E F
|
||||
def compress(data, selectors):
|
||||
return (d for d, s in zip(data, selectors) if s)
|
||||
|
||||
# count(4, 3) --> 4 7 10 13 16 19 ....
|
||||
def count(start=0, step=1):
|
||||
while True:
|
||||
yield start
|
||||
start += step
|
||||
|
||||
|
||||
def cycle(p):
|
||||
# cycle('abc') --> a b c a b c a b c a ....
|
||||
def cycle(iterable):
|
||||
try:
|
||||
len(p)
|
||||
except TypeError:
|
||||
# len() is not defined for this type. Assume it is
|
||||
# a finite iterable so we must cache the elements.
|
||||
len(iterable)
|
||||
except TypeError: # len() not defined: Assume p is a finite iterable: We cache the elements.
|
||||
cache = []
|
||||
for i in p:
|
||||
for i in iterable:
|
||||
yield i
|
||||
cache.append(i)
|
||||
p = cache
|
||||
while p:
|
||||
yield from p
|
||||
iterable = cache
|
||||
while iterable:
|
||||
yield from iterable
|
||||
|
||||
# # dropwhile(lambda x: x<5, [1,4,6,4,1]) --> 6 4 1
|
||||
def dropwhile(predicate, iterable):
|
||||
it = iter(iterable)
|
||||
for x in it:
|
||||
if not predicate(x):
|
||||
yield x
|
||||
break
|
||||
for x in it:
|
||||
yield x
|
||||
|
||||
def repeat(el, n=None):
|
||||
if n is None:
|
||||
# filterfalse(lambda x: x%2, range(10)) --> 0 2 4 6 8
|
||||
def filterfalse(predicate, iterable):
|
||||
if predicate is None:
|
||||
predicate = bool
|
||||
for x in iterable:
|
||||
if not predicate(x):
|
||||
yield x
|
||||
|
||||
# groupby('aaaabbbccdaa'))) --> ('a', gen1) ('b', gen2) ('c', gen3) ('d', gen4) ('a', gen5)
|
||||
# where gen1 --> a a a a, gen2 --> b b b, gen3 --> c c, gen4 --> d, gen5 --> a a
|
||||
def groupby(iterable, key=None):
|
||||
it = iter(iterable)
|
||||
keyf = key if key is not None else lambda x: x
|
||||
def ggen(ktgt):
|
||||
nonlocal cur, kcur
|
||||
while kcur == ktgt:
|
||||
yield cur
|
||||
try:
|
||||
cur = next(it); kcur = keyf(cur)
|
||||
except StopIteration:
|
||||
break
|
||||
kcur = kold = object() # need an object that never can be a returned from key function
|
||||
while True:
|
||||
yield el
|
||||
else:
|
||||
for i in range(n):
|
||||
yield el
|
||||
|
||||
|
||||
def chain(*p):
|
||||
for i in p:
|
||||
yield from i
|
||||
|
||||
|
||||
def islice(p, start, stop=(), step=1):
|
||||
if stop == ():
|
||||
stop = start
|
||||
start = 0
|
||||
# TODO: optimizing or breaking semantics?
|
||||
if start >= stop:
|
||||
while kcur == kold: # not all iterables with the same (old) key were used up by ggen, so use them up here
|
||||
try:
|
||||
cur = next(it); kcur = keyf(cur)
|
||||
except StopIteration:
|
||||
return
|
||||
it = iter(p)
|
||||
kold = kcur
|
||||
yield (kcur, ggen(kcur))
|
||||
|
||||
# islice('abcdefghij', 2, None, 3)) --> c f i
|
||||
# islice(range(10), 2, 6, 2)) --> 2 4
|
||||
def islice(iterable, *sargs):
|
||||
if len(sargs) < 1 or len(sargs) > 3:
|
||||
raise TypeError('islice expected at least 2, at most 4 arguments, got {:d}'.format(len(sargs)+1))
|
||||
step = 1 if len(sargs) < 3 else sargs[2]
|
||||
step = 1 if step is None else step
|
||||
if step <= 0:
|
||||
raise ValueError('step for islice() must be a positive integer or None')
|
||||
start = 0 if len(sargs) < 2 else sargs[0]
|
||||
stop = sargs[0] if len(sargs) == 1 else sargs[1]
|
||||
it = iter(iterable)
|
||||
try:
|
||||
for i in range(start):
|
||||
next(it)
|
||||
|
||||
while True:
|
||||
if stop is not None and start >= stop:
|
||||
return
|
||||
yield next(it)
|
||||
for i in range(step - 1):
|
||||
next(it)
|
||||
start += step
|
||||
if start >= stop:
|
||||
except StopIteration:
|
||||
return
|
||||
|
||||
# pairwise(range(5)) --> (0,1) (1,2) (2,3) (3,4)
|
||||
# pairwise('abcdefg') --> ('a','b') ('b','c') ('c','d') ('d','e') ('e','f') ('f','g')
|
||||
def pairwise(iterable):
|
||||
it = iter(iterable)
|
||||
try:
|
||||
l = next(it)
|
||||
while True:
|
||||
c = next(it)
|
||||
yield l, c
|
||||
l = c
|
||||
except StopIteration:
|
||||
return
|
||||
|
||||
def tee(iterable, n=2):
|
||||
return [iter(iterable)] * n
|
||||
# permutations('ABCD', 2) --> AB AC AD BA BC BD CA CB CD DA DB DC
|
||||
# permutations(range(3)) --> 012 021 102 120 201 210
|
||||
def permutations(iterable, r=None):
|
||||
pool = tuple(iterable)
|
||||
n = len(pool)
|
||||
r = n if r is None else r
|
||||
if r > n:
|
||||
return
|
||||
indices = list(range(n))
|
||||
cycles = list(range(n, n - r, -1))
|
||||
yield tuple(pool[i] for i in indices[:r])
|
||||
while n:
|
||||
for i in reversed(range(r)):
|
||||
cycles[i] -= 1
|
||||
if cycles[i] == 0:
|
||||
indices[i:] = indices[i + 1 :] + indices[i : i + 1]
|
||||
cycles[i] = n - i
|
||||
else:
|
||||
j = cycles[i]
|
||||
indices[i], indices[-j] = indices[-j], indices[i]
|
||||
yield tuple(pool[i] for i in indices[:r])
|
||||
break
|
||||
else:
|
||||
return
|
||||
|
||||
# product('ABCD', 'xy') --> ('A','x') ('A','y') ('B','x') ('B','y') ('C','x') ('C','y') ('D','x') ('D','y')
|
||||
# product(range(2), repeat=3) --> 000 001 010 011 100 101 110 111 # but in tuples, of course
|
||||
def product(*args, repeat=1):
|
||||
pools = [tuple(pool) for pool in args] * repeat
|
||||
result = [[]]
|
||||
for pool in pools:
|
||||
result = [x + [y] for x in result for y in pool]
|
||||
for prod in result:
|
||||
yield tuple(prod)
|
||||
|
||||
# repeat(10, 3) --> 10 10 10
|
||||
def repeat(obj, times=None):
|
||||
if times is None:
|
||||
while True:
|
||||
yield obj
|
||||
else:
|
||||
for _ in range(times):
|
||||
yield obj
|
||||
|
||||
# starmap(pow, [(2,5), (3,2), (10,3)]) --> 32 9 1000
|
||||
def starmap(function, iterable):
|
||||
for args in iterable:
|
||||
yield function(*args)
|
||||
|
||||
# takewhile(lambda x: x<5, [1,4,6,4,1]) --> 1 4
|
||||
def takewhile(predicate, iterable):
|
||||
for x in iterable:
|
||||
if predicate(x):
|
||||
yield x
|
||||
else:
|
||||
break
|
||||
|
||||
def accumulate(iterable, func=lambda x, y: x + y):
|
||||
# tee(range(2,10), 3) --> (it1, it2, it3) all parallel generators, but dependent on original generator (e.g. range(2,10))
|
||||
# --> (min(it1), max(it2), sum(it3)) --> (2, 9, 44)
|
||||
def tee(iterable, n=2):
|
||||
if iter(iterable) is not iter(iterable): # save buffer for special cases that iterable is range, tuple, list ...
|
||||
return [iter(iterable) for _ in range(n)] # that have independent iterators
|
||||
it = iter(iterable)
|
||||
if n < 1:
|
||||
return ()
|
||||
elif n == 1:
|
||||
return (it,)
|
||||
buf = [] # Buffer, contains stored values from itr
|
||||
ibuf = [0]*n # Indices of the individual generators, could be array('H', [0]*n)
|
||||
def gen(k): # but we have no 0 in ibuf in MP
|
||||
nonlocal buf, ibuf # These are bound to the generators as closures
|
||||
while True:
|
||||
if ibuf[k] < len(buf): # We get an object stored in the buffer.
|
||||
r = buf[ibuf[k]]
|
||||
ibuf[k] += 1
|
||||
if ibuf[k] == 1: # If we got the first object in the buffer,
|
||||
if 0 not in ibuf: # then check if other generators do not wait anymore on it
|
||||
buf.pop(0) # so it may be popped left. Afterwards decrease all indices by 1.
|
||||
for i in range(n):
|
||||
ibuf[i] -= 1
|
||||
elif ibuf[k] == len(buf):
|
||||
try:
|
||||
acc = next(it)
|
||||
r = next(it)
|
||||
buf.append(r)
|
||||
ibuf[k] += 1
|
||||
except StopIteration:
|
||||
return
|
||||
yield acc
|
||||
for element in it:
|
||||
acc = func(acc, element)
|
||||
yield acc
|
||||
yield r # The returned generators are not thread-safe. For that the access to the
|
||||
return tuple(gen(i) for i in range(n)) # shared buf and ibuf should be protected by locks.
|
||||
|
||||
# zip_longest('ABCD', 'xy', fillvalue='-') --> ('A','x') ('B','y') ('C','-') ('D','-')
|
||||
def zip_longest(*args, fillvalue=None):
|
||||
iterators = [iter(it) for it in args]
|
||||
num_active = len(iterators)
|
||||
if not num_active:
|
||||
return
|
||||
while True:
|
||||
values = []
|
||||
for i, it in enumerate(iterators):
|
||||
try:
|
||||
value = next(it)
|
||||
except StopIteration:
|
||||
num_active -= 1
|
||||
if not num_active:
|
||||
return
|
||||
iterators[i] = repeat(fillvalue)
|
||||
value = fillvalue
|
||||
values.append(value)
|
||||
yield tuple(values)
|
||||
|
||||
|
||||
# # Full analog of CPython builtin iter with 2 arguments
|
||||
# def iter(*args):
|
||||
#
|
||||
# if len(args) == 1:
|
||||
# return builtins.iter(args[0])
|
||||
#
|
||||
# class _iter:
|
||||
#
|
||||
# def __init__(self, args):
|
||||
# self.f, self.sentinel = args
|
||||
# def __next__(self):
|
||||
# v = self.f()
|
||||
# if v == self.sentinel:
|
||||
# raise StopIteration
|
||||
# return v
|
||||
#
|
||||
# return _iter(args)
|
||||
|
||||
|
|
|
|||
|
|
@ -1,3 +1,3 @@
|
|||
metadata(version="0.2.3")
|
||||
metadata(version="0.5.0")
|
||||
|
||||
module("itertools.py")
|
||||
|
|
|
|||
|
|
@ -1,24 +1,127 @@
|
|||
import itertools
|
||||
|
||||
assert list(itertools.islice(list(range(10)), 4)) == [0, 1, 2, 3]
|
||||
assert list(itertools.islice(list(range(10)), 2, 6)) == [2, 3, 4, 5]
|
||||
assert list(itertools.islice(list(range(10)), 2, 6, 2)) == [2, 4]
|
||||
|
||||
|
||||
def g():
|
||||
while True:
|
||||
yield 123
|
||||
|
||||
|
||||
assert list(itertools.islice(g(), 5)) == [123, 123, 123, 123, 123]
|
||||
|
||||
assert list(itertools.islice(itertools.cycle([1, 2, 3]), 10)) == [1, 2, 3, 1, 2, 3, 1, 2, 3, 1]
|
||||
assert list(itertools.islice(itertools.cycle(reversed([1, 2, 3])), 7)) == [3, 2, 1, 3, 2, 1, 3]
|
||||
|
||||
assert list(itertools.starmap(lambda x, y: x * y, [[1, 2], [2, 3], [3, 4]])) == [2, 6, 12]
|
||||
|
||||
# accumulate
|
||||
assert list(itertools.accumulate([])) == []
|
||||
assert list(itertools.accumulate([0])) == [0]
|
||||
assert list(itertools.accumulate([0, 2, 3])) == [0, 2, 5]
|
||||
assert list(itertools.accumulate(reversed([0, 2, 3]))) == [3, 5, 5]
|
||||
assert list(itertools.accumulate([1, 2, 3], lambda x, y: x * y)) == [1, 2, 6]
|
||||
assert list(itertools.accumulate([1,2,3,4,5], func=lambda x, y: x - y, initial=10)) == [10, 9, 7, 4, 0, -5]
|
||||
|
||||
# chain
|
||||
assert list(itertools.chain()) == []
|
||||
assert list(itertools.chain([],[],[])) == []
|
||||
assert list(itertools.chain(range(3),[2*(i+1) for i in range(4)])) == [0, 1, 2, 2, 4, 6, 8]
|
||||
assert list(itertools.chain('abcd',[],range(5))) == ['a', 'b', 'c', 'd', 0, 1, 2, 3, 4]
|
||||
|
||||
assert list(itertools.chain.from_iterable([])) == []
|
||||
assert list(itertools.chain.from_iterable(['ABC', 'DEF'])) == ['A', 'B', 'C', 'D', 'E', 'F']
|
||||
|
||||
# combinations
|
||||
assert list(itertools.combinations('', 1)) == []
|
||||
assert list(itertools.combinations('ABCD', 0)) == [()]
|
||||
assert list(itertools.combinations('ABCD', 1)) == [('A',), ('B',), ('C',), ('D',)]
|
||||
assert list(itertools.combinations('ABCD', 3)) == [('A', 'B', 'C'), ('A', 'B', 'D'), ('A', 'C', 'D'), ('B', 'C', 'D')]
|
||||
assert list(itertools.combinations('ABCD', 4)) == [('A', 'B', 'C', 'D')]
|
||||
assert list(itertools.combinations('ABCD', 5)) == []
|
||||
assert len(list(itertools.combinations(range(7), 4))) == 35
|
||||
assert len(set(itertools.combinations(range(7), 4))) == 35
|
||||
|
||||
# combinations with replacement
|
||||
assert list(itertools.combinations_with_replacement('ABCD', 0)) == [()]
|
||||
assert list(itertools.combinations_with_replacement('ABCD', 1)) == [('A',), ('B',), ('C',), ('D',)]
|
||||
assert list(itertools.combinations_with_replacement('ABC', 2)) == [('A', 'A'), ('A', 'B'), ('A', 'C'), ('B', 'B'), ('B', 'C'), ('C', 'C')]
|
||||
assert list(itertools.combinations_with_replacement('ABC', 3)) == [('A', 'A', 'A'), ('A', 'A', 'B'), ('A', 'A', 'C'), ('A', 'B', 'B'), ('A', 'B', 'C'), ('A', 'C', 'C'), ('B', 'B', 'B'), ('B', 'B', 'C'), ('B', 'C', 'C'), ('C', 'C', 'C')]
|
||||
|
||||
# compress
|
||||
assert tuple(itertools.compress('ABCDEF', (1,0,1,0,1,1))) == ('A', 'C', 'E', 'F')
|
||||
assert tuple(itertools.compress('ABCDEF', (1,0,1,1,0))) == ('A', 'C', 'D')
|
||||
|
||||
# count
|
||||
it = itertools.count(4, 3)
|
||||
for _ in range(200):
|
||||
n = next(it)
|
||||
assert list(next(it) for _ in range(5)) == [604, 607, 610, 613, 616]
|
||||
|
||||
# cycle
|
||||
it = itertools.cycle(iter('abcde'))
|
||||
assert list(next(it) for _ in range(12)) == ['a', 'b', 'c', 'd', 'e', 'a', 'b', 'c', 'd', 'e', 'a', 'b']
|
||||
it = itertools.cycle([2, 4, 'x'])
|
||||
assert list(next(it) for _ in range(7)) == [2, 4, 'x', 2, 4, 'x', 2]
|
||||
|
||||
# dropwhile
|
||||
assert list(itertools.dropwhile(lambda x: x<5, [1,4,6,4,1])) == [6, 4, 1]
|
||||
assert list(itertools.dropwhile(lambda x: ord(x)<118, '')) == []
|
||||
assert list(itertools.dropwhile(lambda x: ord(x)<118, 'dropwhile')) == ['w', 'h', 'i', 'l', 'e']
|
||||
|
||||
# filterfalse
|
||||
assert list(itertools.filterfalse(lambda x: ord(x)<110, 'dropwhile')) == ['r', 'o', 'p', 'w']
|
||||
|
||||
# groupby
|
||||
assert list(((k,''.join(g)) for k,g in itertools.groupby('aaaabbbccdaa'))) == [('a', 'aaaa'), ('b', 'bbb'), ('c', 'cc'), ('d', 'd'), ('a', 'aa')]
|
||||
|
||||
# islice
|
||||
assert ''.join(itertools.islice('', 2, 5)) == ''
|
||||
assert ''.join(itertools.islice('abcdefgh', 2, 5)) == 'cde'
|
||||
assert ''.join(itertools.islice('abcdefghij', 2, None, 3)) == 'cfi'
|
||||
assert ''.join(itertools.islice('abcdefghij', 2, None)) == 'cdefghij'
|
||||
assert ''.join(itertools.islice('abcdefghij', 6)) == 'abcdef'
|
||||
assert ''.join(itertools.islice('abcdefghij', 6, 6)) == ''
|
||||
assert list(itertools.islice(range(10), 2, 6, 2)) == [2, 4]
|
||||
assert list(itertools.islice(itertools.cycle([1, 2, 3]), 10)) == [1, 2, 3, 1, 2, 3, 1, 2, 3, 1]
|
||||
|
||||
# pairwise
|
||||
assert list(itertools.pairwise(range(5))) == [(0, 1), (1, 2), (2, 3), (3, 4)]
|
||||
assert list((''.join(t) for t in itertools.pairwise('abcdefg'))) == ['ab', 'bc', 'cd', 'de', 'ef', 'fg']
|
||||
assert list((''.join(t) for t in itertools.pairwise('ab'))) == ['ab']
|
||||
assert list((''.join(t) for t in itertools.pairwise('a'))) == []
|
||||
assert list((''.join(t) for t in itertools.pairwise(''))) == []
|
||||
|
||||
# permutations
|
||||
assert list(itertools.permutations('', 1)) == []
|
||||
assert list((''.join(t) for t in itertools.permutations('a', 2))) == []
|
||||
assert list((''.join(t) for t in itertools.permutations('abcd', 0))) == ['']
|
||||
assert list((''.join(t) for t in itertools.permutations('ab', 2))) == ['ab', 'ba']
|
||||
assert list((''.join(t) for t in itertools.permutations('abcd', 2))) == ['ab', 'ac', 'ad', 'ba', 'bc', 'bd', 'ca', 'cb', 'cd', 'da', 'db', 'dc']
|
||||
assert list(itertools.permutations(range(3))) == [(0, 1, 2), (0, 2, 1), (1, 0, 2), (1, 2, 0), (2, 0, 1), (2, 1, 0)]
|
||||
|
||||
# product
|
||||
assert list(itertools.product()) == [()]
|
||||
assert list(itertools.product(range(2), repeat=0)) == [()]
|
||||
assert list((''.join(t) for t in itertools.product('ABC', 'xy'))) == ['Ax', 'Ay', 'Bx', 'By', 'Cx', 'Cy']
|
||||
assert list((''.join(t) for t in itertools.product('A', 'xy', repeat=2))) == ['AxAx', 'AxAy', 'AyAx', 'AyAy']
|
||||
assert list((''.join(map(str,t)) for t in itertools.product(range(2), repeat=3))) == ['000','001','010','011','100','101','110','111']
|
||||
|
||||
# repeat
|
||||
assert list(itertools.repeat(10, 0)) == []
|
||||
assert list(itertools.repeat(10, 1)) == [10]
|
||||
assert list(itertools.repeat(10, 3)) == [10, 10, 10]
|
||||
|
||||
# starmap
|
||||
assert list(itertools.starmap(pow, [])) == []
|
||||
assert list(itertools.starmap(pow, [(2,5), (3,2), (10,3)])) == [32, 9, 1000]
|
||||
assert list(itertools.starmap(lambda x, y: x * y, [[1, 2], [2, 3], [3, 4]])) == [2, 6, 12]
|
||||
|
||||
# takewhile
|
||||
assert list(itertools.takewhile(lambda x: x<5, [1,4,6,4,1])) == [1, 4]
|
||||
assert list(itertools.takewhile(lambda x: ord(x)<118, 'dropwhile')) == ['d', 'r', 'o', 'p']
|
||||
|
||||
# tee
|
||||
def genx(n):
|
||||
i=1;
|
||||
while True:
|
||||
yield i; i+=1
|
||||
if i >n:
|
||||
return
|
||||
it1, it2, it3 = itertools.tee(genx(1000), 3); _ = next(it1) # case of iterable that is unique; iterate once
|
||||
assert [min(it1), max(it2), sum(it3)] == [2, 1000, 500500]
|
||||
it1, it2, it3 = itertools.tee(range(2,10), 3); _ = next(it1) # iterable that is not unique; iterate once
|
||||
assert [min(it1), max(it2), sum(it3)] == [3, 9, 44] # the min is increased, other iterators remained full
|
||||
|
||||
# zip_longest
|
||||
assert list(itertools.zip_longest('', '')) == []
|
||||
assert list(itertools.zip_longest('', '', fillvalue='-')) == []
|
||||
assert list(itertools.zip_longest('', 'xy')) == [(None, 'x'), (None, 'y')]
|
||||
assert list(itertools.zip_longest('', 'xy', fillvalue='-')) == [('-', 'x'), ('-', 'y')]
|
||||
assert list(itertools.zip_longest('ABCD', 'xy', fillvalue='-')) == [('A','x'),('B','y'),('C','-'),('D','-')]
|
||||
|
||||
|
|
|
|||
Ładowanie…
Reference in New Issue