[R] Calculate median from counts and values

From: David Finlayson <david.p.finlayson_at_gmail.com>
Date: Wed 04 May 2005 - 10:39:00 EST


I am tangled with a syntax question. I want to calculate basic statistics for a large dataset provided in weights and values and I can't figure out an elegant way to expand the data.

For example here are the counts:

> counts

    n4 n3 n2 n1 p0 p1 p2 p3 p4
1 0 0 0 1 1 3 16 55 24
2 0 0 0 0 2 8 28 47 15
3 1 17 17 13 4 5 12 24 8
...

and the values:

> values

      n4 n3 n2 n1 p0 p1 p2 p3 p4 [1,] 16 8 4 2 1 0.5 0.25 0.125 0.0625

What I want for each row is something like this (shown for row 1):

c( rep(16, 0), rep(8, 0), rep(4, 0), rep(2, 1), rep(1, 1), rep(0.5, 3), rep(0.25, 16), rep(0.125, 55), rep(0.0625, 24))

I am sure that this is a one-liner for an R-master, but I can't figure it out without a set of nested for loops iterating over each row in counts.

David

-- 
David Finlayson
Marine Geology & Geophysics
School of Oceanography
Box 357940
University of Washington
Seattle, WA  98195-7940
USA

Office: Marine Sciences Building, Room 112
Phone: (206) 616-9407
Web: http://students.washington.edu/dfinlays/

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Received on Wed May 04 10:45:45 2005

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