[Numpy-discussion] Finding values in an array

[Robert Kern]

On Fri, Nov 28, 2014 at 8:22 AM, Julian Taylor <
jtaylor.debian at googlemail.com> wrote:
>
> On 28.11.2014 04:15, Alexander Belopolsky wrote:
> > I probably miss something very basic, but how given two arrays a and b,
> > can I find positions in a where elements of b are located?  If a were
> > sorted, I could use searchsorted, but I don't want to get valid
> > positions for elements that are not in a.  In my case, a has unique
> > elements, but in the general case I would accept the first match.  In
> > other words, I am looking for an array analog of list.index() method.
>
> np.where(np.in1d(a, b))

Only if the matching elements in `b` have the same order as they do in `a`.

--
Robert Kern
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