[Numpy-discussion] Masking an array with another array

[Neil Crighton]

 <josef.pktd <at> gmail.com> writes:

> setmember1d is very fast compared to the other solutions for large b.
> 
> However, setmember1d requires that both arrays only have unique elements.
> 
> So it doesn't work if, for example, your first array is a data vector
> with member ship in different groups (therefore not only uniques), and
> the second array is the sub group that you want to check.
> 

Note there's a patch waiting to be reviewed that adds another version of
setmember_1d for non-unique inputs.

http://projects.scipy.org/numpy/ticket/1036


Neil