On Feb 7, 2010, at 1:57 PM, James Rome wrote:
On 2/7/2010 1:35 PM, David Winsemius wrote:But to answer your
question:
apply(d, 1, function(z) aggregate(z, by=list(s), FUN=sum) )
David,
That works, but I do not understand why I could not use aggregate
directly. And the answer comes out as a list, which thus far baffles
me.
It comes out as a data.frame, ... just as promised in the help page.
How do I get the answer as a matrix in my original code, which I
modified to use apply?
You could coerce either maxrdf or the aggregate returns to a matrix
with as.matrix or data.matrix.
ha = matrix(nrow=7, ncol=24)
colnames(ha) = as.character(c(0:23))
rownames(ha) = rownames(maxrdf)
for(j in 1:7) {
x = apply(maxrdf[j,], 1, function(z) aggregate(z, by=list(s),
FUN=sum) )
ha[j,] = x[[1]][2]
}
Unfortunately, ha gets converted into a list, and then I can't use it
for my plots. And you can probably educate me on how to get what I am
aiming for (a matrix with the rows as the days, the columns as the
hours, and the content as the hourly sum of the 15-minute chunks)
without using the above for loop.
apply( data.matrix(maxrdf), 1 # loops over the rows
function(z) aggregate(z, by=s, sum)
)
#Gives you a bunch of dataframes produced by the serial application of
aggregate.
sapply(apply(maxrdf, 1, function(z) aggregate(z, by=list(s), sum) ),
'[', 2)
#Gives you a list of vectors by day...almost what you wanted ...
# the ' "[", 2' part is the extraction of the second column of the
dataframe
# And what I think you were asking for:
do.call(rbind,
sapply(apply(maxrdf, 1,
function(z) aggregate(z, by=list(s), sum) ), '[', 2) )
# ... as a matrix with named rows
[,1] [,2] [,3] [,4] [,5] [,6] [,7] [,8] [,9] [,10] [,11]
[,12] [,13] [,14] [,15] [,16] [,17]
Sunday.x 1 0 0 0 2 0 0 0 15 0
6 5 30 24 3 1 8
Monday.x 4 1 2 0 3 0 0 12 21 26
21 31 25 1 0 0 13
Tuesday.x 1 4 2 1 8 22 23 34 26 22
17 23 37 13 32 0 15
Wednesday.x 7 4 2 1 11 24 27 39 19 20
8 20 24 1 20 12 7
Thursday.x 0 0 1 0 0 13 22 0 16 17
13 7 0 13 39 30 31
Friday.x 6 3 7 0 9 0 18 25 19 22
10 27 25 5 1 0 9
Saturday.x 7 3 1 1 8 20 31 41 23 19
17 26 0 1 1 1 11
[,18] [,19] [,20] [,21] [,22] [,23] [,24]
Sunday.x 39 37 28 21 20 1 11
Monday.x 35 7 0 28 6 5 0
Tuesday.x 37 37 37 27 23 22 15
Wednesday.x 18 13 28 30 18 0 0
Thursday.x 34 37 35 29 31 19 17
Friday.x 28 32 36 32 29 20 20
Saturday.x 30 32 32 7 0 0 0
Thanks for the help,
Jim
David Winsemius, MD
Heritage Laboratories
West Hartford, CT
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