Re: How can I this efficiently? common rows in two data sets

[Keith Goodman]

I would stack the two datasets into a single dataset. Then I would use
sortrows on the time column. Then do time(2:end)-time(1:end-1)==0 to
find matches. Then pull the matched rows out into a new matrix.

On 5/12/05, Rick Niles <address@hidden> wrote:
> OK I have a problem I hit a lot and I haven't come up with a good way to
> do this Octave.  I was wondering if there's a good way to do this or if
> it's a opportunity for another built-in oct-file if there's not a good
> way to do it with the current set of the functions.
> 
>  I have two data files, each has one column that represents "time".  But
> they don't start and stop at the same time and either may have random
> drop-outs (no-data) for any amount of time.   The obvious thing to do
> make a common data set that only contains the times (rows) for which I
> have data from both sets.
> 
> I tried using "intersection()" on the time columns and doing a for loop
> with "find()" for each time value one at a time to get the indexes that
> have common time, but on a large data set it's really slow and obviously
> not very efficient.
> 
> As lots of people use Octave to process real data sets it seems like
> there should be a good way to do this.
> 
> Any ideas?
> 
>     Thanks,
>     Rick Niles.
> 
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