Manipulating Arrays in Python

This is how you extract elements

>>> from numpy import *
>>> stuff=arange(8).reshape(4,2)
>>> stuff
array([[0, 1],
       [2, 3],
       [4, 5],
       [6, 7]])
>>> extract(stuff>4,stuff)
array([5, 6, 7])

This is how you extract elements from an array by the index of another

>>> a
[1, 2, 3]
>>> b
[3, 4, 5]
>>> barr=array(b)
>>> aarr=array(a)
>>> extract(aarr>1,barr)
array([4, 5])