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Code to merge two ordered iterables
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def _le(left, right): | |
return left if left <= right else right | |
def merge(left, right, cmp=_le): | |
""" | |
Merges two ordered iterables (left and right) keeping result ordered according to cmp. | |
:param left: iterable | |
:param right: iterable | |
:param cmp: callable which receive one element from left and another from right and returns the on to be merged. | |
Default is less or equal then. Ex: | |
def _le(left, right): | |
return left if left <= right else right | |
:return: merging result of left and right | |
Usage: | |
>>> from merge import merge | |
>>> print(list(merge([1, 2], [3, 4]))) | |
[1, 2, 3, 4] | |
>>> print(list(merge([1, 2], [0, 4]))) | |
[0, 1, 2, 4] | |
>>> print(list(merge(range(3), range(2,5)))) | |
[0, 1, 2, 2, 3, 4] | |
""" | |
left = iter(left) | |
right = iter(right) | |
class Finished: | |
pass | |
def next_or_finished(iterable): | |
try: | |
return next(iterable) | |
except StopIteration: | |
return Finished | |
l = next_or_finished(left) | |
r = next_or_finished(right) | |
while l is not Finished and r is not Finished: | |
result = cmp(l, r) | |
yield result | |
if result is l: | |
l = next_or_finished(left) | |
else: | |
r = next_or_finished(right) | |
def finish(ele, iterable): | |
while ele is not Finished: | |
yield ele | |
ele = next_or_finished(iterable) | |
yield from finish(l, left) | |
yield from finish(r, right) |
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