dataframe - create column in R data frame adding values in several columns above the value in a different column -

this problem have dataframe this

df=data.frame(v1=c(24,15, 0, 7,36,10), c1=c(22,15,0,0,28,11), v2=c(0,10,0,19,0,0), c2=c(0,7,0,22,0,0), v3=c(54,22,28,55,62,38), c3=c(44,23,22,66,71,44), cut=c(20,35,40,15,40,30)) 

that looks this

  v1 c1 v2 c2 v3 c3 cut 1 24 22  0  0 54 44  20 2 15 15 10  7 22 23  35 3  0  0  0  0 28 22  40 4  7  0 19 22 55 66  15 5 36 28  0  0 62 71  40 6 10 11  0  0 38 44  30 

i need create new column adds values of columns v1,v2,v3 (there more in real case), when above value in column "cut"

so, in case column "sum" be:

sum 78  0  0 64 62 38 

i hope not obvious.

r> df$sum = apply(df[c(grep("v", names(df), value = true), "cut")], 1, function(y) sum(y[y > y["cut"]]) ) r> df   v1 c1 v2 c2 v3 c3 cut sum 1 24 22  0  0 54 44  20  78 2 15 15 10  7 22 23  35   0 3  0  0  0  0 28 22  40   0 4  7  0 19 22 55 66  15  74 5 36 28  0  0 62 71  40  62 6 10 11  0  0 38 44  30  38 

here's mapply approach

r> df$sum = do.call(mapply, c(function(...) { y = c(...); sum(y[y > y["cut"]]) }, df[c(grep("v", names(df), value = true), "cut")]) ) r> df   v1 c1 v2 c2 v3 c3 cut sum 1 24 22  0  0 54 44  20  78 2 15 15 10  7 22 23  35   0 3  0  0  0  0 28 22  40   0 4  7  0 19 22 55 66  15  74 5 36 28  0  0 62 71  40  62 6 10 11  0  0 38 44  30  38