Hello R-community,
I am trying to populate a column (doy) in a large dataset with the first
column number that exceeds the value in another column (thold) using the
'apply' function.
Sample data:
pt D1 D17 D33 D49 D65 D81 D97 D113 D129 D145 D161 D177
D193 D209 D225 D241 D257
1 39177 0 0 0 0 0 0 0 0 0.4336 0.4754 0.5340667 0.5927334
0.6514 0.6966 0.5900 0.5583 0.5676
2 39178 0 0 0 0 0 0 0 0 0.3420 0.4543 0.5397666 0.6252333
0.7107 0.7123 0.5591 0.4617 0.4206
3 39164 0 0 0 0 0 0 0 0 0.4830 0.4943 0.5740333 0.6537667
0.7335 0.6255 0.6228 0.5255 0.5436
4 39143 0 0 0 0 0 0 0 0 0.3088 0.3753 0.4466000 0.5179000
0.5892 0.6468 0.4794 0.4411 0.4307
5 39144 0 0 0 0 0 0 0 0 0.3390 0.4152 0.5147000 0.6142000
0.7137 0.6914 0.6381 0.5704 0.5619
6 39146 0 0 0 0 0 0 0 0 0.4232 0.4442 0.5084000 0.5726000
0.6368 0.5896 0.4703 0.4936 0.5353
D273 D289 D305 D321 D337 D353 thold doy
1 0.4682 0.35115 0.2341 0.11705 0 0 0.406825 0
2 0.3867 0.25780 0.1289 0.00000 0 0 0.420600 0
3 0.5541 0.46195 0.3698 0.18490 0 0 0.459200 0
4 0.3632 0.34355 0.3239 0.00000 0 0 0.477800 0
5 0.5347 0.49760 0.4605 0.00000 0 0 0.526350 0
6 0.4067 0.39685 0.3870 0.00000 0 0 0.511900 0
For the first record in above example I would expect doy = 129.
I can achieve this with the following loop, but it takes several days to run
and there must be a more efficient solution:
for (i in (1:152000)) {
t=which(data[i,2:24]>data[i,25])
r=min(t)
data[i,26]=(r-1)*16+1
}
How do I write this using 'apply' or another function that will be more
efficient?
I have tried the following:
data$doy=apply(which(data[,2:24]>data[,25]),1,min)
Which returns the following error message:
"Error in apply(which(new[, 2:24] > new[, 25]), 1, min) :
dim(X) must have a positive length"
Any help would be much appreciated.
Nathan
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