[Numpy-discussion] yet another indexing question

Neal Becker ndbecker2@gmail....
Fri Oct 14 07:04:39 CDT 2011


suppose I have:

In [10]: u
Out[10]: 
array([[0, 1, 2, 3, 4],
       [5, 6, 7, 8, 9]])

And I have a vector v:
 v = np.array ((0,1,0,1,0))

I want to form an output vector which selects items from u where v is the index 
of the row of u to be selected.

In the above example, I want:

w = [0,6,2,8,4]

I can't seem to find a syntax that does this.

Now, more importantly, I need the result to be a reference to the original array 
(not a copy), because I'm going to use it on the LHS of an assignment.  Is this 
possible?



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