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What is the slickest way to transpose a square list of lists (tuple oftuples)?

My way is ugly. These has to be a better way.

Thanks,
Gerard
Jan 8 '06 #1
3 3110
Gerard Brunick wrote:
My way is ugly. These has to be a better way.

Thanks,
Gerard

Ugly is not necessary not the slickest. To do better, there must be
something to compare to, right?

Claudio
Jan 8 '06 #2
On Sun, 08 Jan 2006 14:27:55 -0500 in comp.lang.pytho n, Gerard Brunick
<gb******@andre w.cmu.edu> wrote:
My way is ugly. These has to be a better way.


This may not be the "slickest" way, but I needed some practice with
list comprehensions (I've never really gotten used to them...)

This works with lists. Making it work with tuples should be a simple
change. Also, it works for the general case of rectangular matrices
rather than being limited to squares.
def transpose(m): """
Transpose the rectangular two-dimentional matrix m.
"""
return [[m[y][x] for y in range(len(m))]for x in
range(len(m[0]))]
def pm(m): """
Print the matrix m. Just to see the results.
"""
for row in m:
print row

td = [range(10) for x in range(10)]
pm(td) [0, 1, 2, 3, 4, 5, 6, 7, 8, 9]
[0, 1, 2, 3, 4, 5, 6, 7, 8, 9]
[0, 1, 2, 3, 4, 5, 6, 7, 8, 9]
[0, 1, 2, 3, 4, 5, 6, 7, 8, 9]
[0, 1, 2, 3, 4, 5, 6, 7, 8, 9]
[0, 1, 2, 3, 4, 5, 6, 7, 8, 9]
[0, 1, 2, 3, 4, 5, 6, 7, 8, 9]
[0, 1, 2, 3, 4, 5, 6, 7, 8, 9]
[0, 1, 2, 3, 4, 5, 6, 7, 8, 9]
[0, 1, 2, 3, 4, 5, 6, 7, 8, 9] pm(transpose(td )) [0, 0, 0, 0, 0, 0, 0, 0, 0, 0]
[1, 1, 1, 1, 1, 1, 1, 1, 1, 1]
[2, 2, 2, 2, 2, 2, 2, 2, 2, 2]
[3, 3, 3, 3, 3, 3, 3, 3, 3, 3]
[4, 4, 4, 4, 4, 4, 4, 4, 4, 4]
[5, 5, 5, 5, 5, 5, 5, 5, 5, 5]
[6, 6, 6, 6, 6, 6, 6, 6, 6, 6]
[7, 7, 7, 7, 7, 7, 7, 7, 7, 7]
[8, 8, 8, 8, 8, 8, 8, 8, 8, 8]
[9, 9, 9, 9, 9, 9, 9, 9, 9, 9] td2 = [range(10) for x in range(5)]
pm(td2) [0, 1, 2, 3, 4, 5, 6, 7, 8, 9]
[0, 1, 2, 3, 4, 5, 6, 7, 8, 9]
[0, 1, 2, 3, 4, 5, 6, 7, 8, 9]
[0, 1, 2, 3, 4, 5, 6, 7, 8, 9]
[0, 1, 2, 3, 4, 5, 6, 7, 8, 9] pm(transpose(td 2)) [0, 0, 0, 0, 0]
[1, 1, 1, 1, 1]
[2, 2, 2, 2, 2]
[3, 3, 3, 3, 3]
[4, 4, 4, 4, 4]
[5, 5, 5, 5, 5]
[6, 6, 6, 6, 6]
[7, 7, 7, 7, 7]
[8, 8, 8, 8, 8]
[9, 9, 9, 9, 9]


Regards,
-=Dave

--
Change is inevitable, progress is not.
Jan 9 '06 #3

Gerard Brunick wrote:
My way is ugly. These has to be a better way.

Thanks,
Gerard


transpose funcitons/methods:

http://numeric.scipy.org/
http://numpy.sourceforge.net/numdoc/numdoc.pdf

Jan 9 '06 #4

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