from goopy.functional import flatten #
http://sourceforge.net/projects/goog-goopy/
b = [(1,2), (3,4), (5,6)]
print flatten(b)
#from goopy.functional import flatten #
http://sourceforge.net/projects/goog-goopy/
def flatten(seq):
"""
Returns a list of the contents of seq with sublists and tuples "exploded".
The resulting list does not contain any sequences, and all inner sequences
are exploded. For example:
>>> flatten([7,(6,[5,4],3),2,1])
[7,6,5,4,3,2,1]
"""
lst = []
for el in seq:
if type(el) == list or type(el) is tuple:
lst.extend(flatten(el))
else:
lst.append(el)
return lst
Chris Rebert wrote:
On Thu, Apr 30, 2009 at 5:56 PM, Ross <ross.j...@gmail.com> wrote:
If I have a list of tuples a = [(1,2), (3,4), (5,6)], and I want to
return a new list of each individual element in these tuples, I can do
it with a nested for loop but when I try to do it using the list
comprehension b = [j for j in i for i in a], my output is b =
[5,5,5,6,6,6] instead of the correct b = [1,2,3,4,5,6]. What am I
doing wrong?
Your comprehension is the identity comprehension (i.e. it effectively
just copies the list as-is).
What you're trying to do is difficult if not impossible to do as a
comprehension.
Here's another approach:
b = list(itertools.chain.from_iterable(a))
And without using a library function:
b = []
for pair in a:
for item in pair:
b.append(item)
Cheers,
Chris
--
Shane Geiger, IT Director
Council For Economic Education / www.councilforeconed.org
sgei...@councilforeconed.org / 402-438-8958
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