length of list is 1D code example

Example: how to vonvert 1 d list to 2d list in pytohn

In [53]: l = [0,1,2,3]

In [54]: def to_matrix(l, n):
    ...:     return [l[i:i+n] for i in xrange(0, len(l), n)]

In [55]: to_matrix(l,2)
Out[55]: [[0, 1], [2, 3]]