How would I succinctly transpose nested lists?
I am writing code to parse a tilemap map from a config file. The map is in the format:
1|2|3|4
1|2|3|4
2|3|4|5
where the numbers represent tiles. I then make this into an integer array:
[[int(tile) for tile in row.split("|")] for row in "1|2|3|4\n1|2|3|4\n2|3|4|5".lstrip("\n").split("\n")]
This produces an array in the format [row][column], but I would prefer it to be [column][row] as in [x][y] so I wouldn't have to address it backwards (i.e. [y][x]). But I can't think of any concise ways of attacking the problem. I have considered reworkin开发者_高级运维g the format using xml syntax through Tiled, but it appears too difficult for a beginner.
Thanks in advance for any responses.
use mylist = zip(*mylist)
:
>>> original = [[1, 2, 3, 4], [1, 2, 3, 4], [2, 3, 4, 5]]
>>> transposed = zip(*original)
>>> transposed
[(1, 1, 2), (2, 2, 3), (3, 3, 4), (4, 4, 5)]
>>> original[2][3]
5
>>> transposed[3][2]
5
How it works: zip(*original)
is equal to zip(original[0], original[1], original[2])
. which in turn is equal to: zip([1, 2, 3, 4], [1, 2, 3, 4], [2, 3, 4, 5]).
def listTranspose( x ):
""" Interpret list of lists as a matrix and transpose """
tups = zip( *x )
return [ list(t) for t in tups ]
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