[R] How can I make this nested loop faster?

[Ludwig Hilger]

Hello everybody, 
I have written a nested for-loop, but as length(uc) > 170,000, this would
take VERY long. I have tried to use sapply or something but I cannot get it
to work, I would be happy if someone could point out to write this more
efficiently. Thank you all,

Ludwig

ergsens <- data.frame(budget = numeric(500))
uc <- unique(rftab$startCell)

for(i in 1:500){
uniquerates <- rlnorm(n = length(uc), mean = -1.6, sd = 1.7)
    for(j in 1:length(uc)){
        rftab$masskg[rftab$startCell == uc[j]] <- uniquerates[j]
    }
ergsens$budget[i] <- sum(rftab$masskg, na.rm = TRUE)/1000
}





-----
Dipl. Geogr. Ludwig Hilger
Wiss. MA
Lehrstuhl für Physische Geographie
Katholische Universität Eichstätt-Ingolstadt
Ostenstraße 18
85072 Eichstätt
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