[Tutor] index of elements in numpy array

Dave Angel d at davea.name
Fri Sep 14 00:39:29 CEST 2012

On 09/13/2012 04:16 PM, Bala subramanian wrote:
> Friends,
> I have a 2D matrix (a numpy array) and i am looping over each row in
> the matrix. I would like to know how i can find the index of each
> element in a while looping a row. Is there any function in numpy.
> Thanks

Perhaps you're asking a more general question.  When iterating over a
collection, sometimes you not only want the object, but you also want
the index you might have used to fetch it.

for row in rows:
   dosomething with row

for index, row in enumerate(rows):
   dosomething with row and with index

Now if rows be a list, or whatever numpy decides to call it, then you
can manipulate the particular one with rows[index].



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