Help, please, beginner)
The number Y is set. There is a data.frame of elements X and Z.
If Y is greater than X, then at these levels X must be summed Z between them.
How to write such a script?
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2 answers
You can use the which function to find indices by condition
I wrote an example, you can see how it works here.
Y = 2; X = c(1, 3, 6); Z = c(1, 2, 3); df = data.frame(X, Z); which(df[,1] < Y) # Для того что бы понять как работает, выводим индексы найденные sum(df[which(df[,1] < Y), 2]) 
Evgenii Izhboldin Evgenii Izhboldin
1,047 2 silver marks 12 bronze marks
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If there are no restrictions on using third-party packages, then I would use dplyr . The code is more understood
library (dplyr) Y <- 4 X <- c(1, 3, 5, 7) Z <- c(10, 20, 30, 40) df <- data.frame(X, Z) # фильтруем исходный `data frame`по условию df.t <- filter(df, df$X < Y) # в результате остается > df.t XZ 1 1 10 2 3 20 # просто суммируем по Z rslt <- sum(df.t$Z) > rslt [1] 30 Roman Sidorin Roman Sidorin
854 4 silver marks 14 bronze marks
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