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Itertools Hacks
Without Itertools
for elem1 in list1:
for elem2 in list2:
process(elem1, elem2)
With Itertools
import itertools
for elem1, elem2 in itertools.product(list1, list2):
process(elem1, elem2)
And of course the itertools example, if it is as simple as a single function call, can be shortened to :
map(process, itertools.product(list1, list2) )
Also it can be extended to multiple lists, iterables etc, without needing to have another nested loop.
Without Itertools
iteration = 0
while True:
process( iteration )
iteration +=1
With Itertools
import itertools
for iteration in itertools.count():
process( iteration)
no risk of ever stepping past the increment line by doing a continue for instance (been there, done that)
Without Itertools
for element in list1 + list2 + list3:
process( element )
With Itertools
import itertools
for element in itertools.chain( list1, list2, list3):
process(element)
Itertools with list of list
import itertools
for element in itertools.chain.from_iterable( list_of_lists ):
process(element)
Without Itertools
for element in my_list:
if condition(element):
break
process(element)
With Itertools
import itertools
for element in itertools.takewhile(lambda x: not condition(x), my_list):
process(element)
Last modified 1yr ago