Jonathan -
Same problem, same solution:
Suppose your data frame is called df:
thematrix = matrix(NA,max(df$x),max(df$y))
thematrix[as.matrix(df[,1:2])] = df[,3]
- Phil Spector
Statistical Computing Facility
Department of Statistics
UC Berkeley
spec...@stat.berkeley.edu
On Tue, 14 Dec 2010, jonathan wrote:
That's so weird, I just signed up on here to ask exactly the same question!
However, I think my issue is like Jessica's who says that her data is like
that, not actually that...
So the issue is not in generating that data on-the-fly but in transforming
it from a data frame to a matrix.
As a more concrete example, I have read the following data in from a file
(around 300,000 rows):
x y z
0 0 687
0 1 64
0 2 71
0 3 55
0 4 52
0 5 51
0 6 38
0 7 38
0 8 54
0 9 49
.........
.........
.........
304979 282977 1
351377 1547980 1
383835 1740541 1
418133 6024710 1
421549 1028572 1
471314 1751836 1
579602 1817393 1
713515 5524385 1
So what I want to do is transform this into a matrix where at position (x,y)
in the matrix I have value z. I am doing this so that I can then do a
filled.contour plot on the data.
I think this is the same as what Jessica is asking...
Regards and many thanks,
Jonathan
UCL Computer Science
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