python - How do you change a one dimensional list into two dimensional using existing elements? -

python - How do you change a one dimensional list into two dimensional using existing elements? -

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how split list evenly sized chunks in python? 45 answers

i reading in text file containing several lists each on own line. elements in given list non-integer x,y co-ordinates need placed array such that:

[x1, y1, x2, y2, x3, y3,....xn, yn]

becomes:

x1 x2 x3....xn

y1 y2 y3....yn

but in same 2d array.

i'm new coding , have tried various methods no avail. right looping on number of co-ordinate pairs , trying append values within loop unsure how this.

this how have started it:

with open('textfile.txt', 'r') infile: line in infile: array=[] number=(line.count(" ")+1)/2 #number of x,y pairs in list in range(0, number-1):

now don't know go here help appreciated! thanks

since new python , dealing numerical data, may want consider de facto standard module such manipulations, numpy. it, problem becomes trivial:

import numpy np = [1,2,3,4,5,6,7,8] print np.array(a).reshape((len(a)/2,2)).t >>> [[1 3 5 7] [2 4 6 8]]

here cast list in numpy array np.array, reshape size want , take transpose t (x1,y1),(x2,y2),... (x1,x2,...),(y1,y2,...).

python