I have this code here:
import itertools
col_groups = [c1+c2 for c1, c2 in itertools.product(d1_columns, d2_columns)]
How can I do something like this without itertools? a non-pythonic way of doing it.
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Why would you want to do that?Peter DeGlopper– Peter DeGlopper2013-11-27 18:49:01 +00:00Commented Nov 27, 2013 at 18:49
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@PeterDeGlopper just curiosity.user3029969– user30299692013-11-27 19:13:34 +00:00Commented Nov 27, 2013 at 19:13
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3 Answers
Perhaps with a nested list comprehension if you just need the cartesian product of two lists.
[ i + j for i in d1_columns for j in d2_columns ]
Comments
You can always use the code given in itertools.product
def product(*args, **kwds):
# product('ABCD', 'xy') --> Ax Ay Bx By Cx Cy Dx Dy
# product(range(2), repeat=3) --> 000 001 010 011 100 101 110 111
pools = map(tuple, args) * kwds.get('repeat', 1)
result = [[]]
for pool in pools:
result = [x+[y] for x in result for y in pool]
for prod in result:
yield tuple(prod)
7 Comments
user3029969
humm thats in interesting way of avoiding to use itertools.
user3029969
I am getting this error tho: unsupported operand type(s) for *: 'map' and 'int'
thefourtheye
What are the parameters you are passing?
user3029969
I have it something like this: I created above function... then I do a function call and pass the function like this inside another function: col_groups = [c1+c2 for c1, c2 in product(d1_columns, d2_columns)]
thefourtheye
Can you please show me what are
dl_columns and d2_columns? |
def colGroups(d1, d2):
answer = []
for c1 in d1:
for c2 in d2:
answer.append(c1+c2)
return answer
Testing:
>>> d1 = list(range(10))
>>> d2 = list(range(10,20))
>>> d1
[0, 1, 2, 3, 4, 5, 6, 7, 8, 9]
>>> d2
[10, 11, 12, 13, 14, 15, 16, 17, 18, 19]
>>> def colGroups(d1, d2):
... answer = []
... for c1 in d1:
... for c2 in d2:
... answer.append(c1+c2)
... return answer
...
>>> colGroups(d1, d2)
[10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28]
... or the nested listcomp equivalent:
colGroups = [c1+c2 for c1 in d1 for c2 in d2]
