[SciPy-User] Finding Positions of Identical Entries in Arrays of Different Size

[Lorenzo Isella]

Dear All,
A problem which should be rather easy, but which is giving me a hard time.
(1) Consider for instance the following two arrays

A=[12,78,98,654,7665,1213,765] and
B=[98,765, 654]

Now, what I need is an efficient way of finding the positions of the 
entries of A equal to the entries of B, that is to say in the case of 
the two arrays above (counting from zero)

C=[2,6,3].
Note that in the example there is a single entry of A equal to the i-th 
entry of B.
I have tried using scipy.where, but unsuccessfully. Any ideas about how 
to code that efficiently?
(2) I would like to extend this to the case where A and B are m times n 
arrays, e.g. consider the case

A= 233 789
      987 734
      890 253
      876 321
      534 489

and

B= 987 734
      876 321
     
and C is now the 1D vector returning the positions of the rows of A 
equal to those of B, i.e.

C=[1, 3].

Any suggestions is really welcome.
Kind Regards

Lorenzo