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R data table splits the column list into a second column list

I have a script that generates a data table with some columns that I want to split into some other columns, and save the results in new columns. Here is an example.

library(data.table)
dt <- data.table(V1 = c( 5.553465,  4.989168,  2.563682,  6.987971, 19.220936),
                 V2 = c(4.248335, 19.768138,  3.840026, 17.411003, 17.939368),
                 V3 = c(9.683953, 15.344424, 11.729091,  7.534210,  5.404000),
                 V4 = c(5.949093,  4.553023,  9.765656, 11.211069,  4.085964),
                 V5 = c(11.814671,  5.460138,  2.492230,  1.48792,  8.164280))

list1 <- list(c("V1", "V2", "V3"))
list2 <- list(c("V2", "V4", "V5"))
listRatio <- list(c("rat1","rat2","rat3"))

I tried various approaches to dividing values ​​in list1 elements by values ​​in list2 elements, to no avail. Two below; does not work.

dt[, (listRatio) := list1/list2]
dt[, c("rat1","rat2","rat3") := mapply(dt, function(x,y) x / y, x = c(V1, V2, V3),  y = c(V2, V4, V5))]
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2 answers

list vector [[, list mget, Map (/) list (listRatio[[1]]).

dt[, (listRatio[[1]]) := Map(`/`, mget(list1[[1]]), mget(list2[[1]]))]
dt
#          V1        V2        V3        V4        V5      rat1      rat2      rat3
#1:  5.553465  4.248335  9.683953  5.949093 11.814671 1.3072098 0.7141147 0.8196549
#2:  4.989168 19.768138 15.344424  4.553023  5.460138 0.2523843 4.3417611 2.8102630
#3:  2.563682  3.840026 11.729091  9.765656  2.492230 0.6676210 0.3932174 4.7062635
#4:  6.987971 17.411003  7.534210 11.211069  1.487920 0.4013537 1.5530190 5.0635854
#5: 19.220936 17.939368  5.404000  4.085964  8.164280 1.0714389 4.3904861 0.6619077

. @Frank, vector , list.

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data.frame

dt <- data.frame(V1 = c( 5.553465,  4.989168,  2.563682,  6.987971, 19.220936),
                 V2 = c(4.248335, 19.768138,  3.840026, 17.411003, 17.939368),
                 V3 = c(9.683953, 15.344424, 11.729091,  7.534210,  5.404000),
                 V4 = c(5.949093,  4.553023,  9.765656, 11.211069,  4.085964),
                 V5 = c(11.814671,  5.460138,  2.492230,  1.48792,  8.164280))

list1 <- list(dt[,c("V1", "V2", "V3")])
list2 <- list(dt[,c("V2", "V4", "V5")])
dt$rat3 <- dt$rat2 <- dt$rat1 <- ""
dt[, c("rat1","rat2","rat3")] <- unlist(list1)/unlist(list2)

         V1        V2        V3        V4        V5      rat1      rat2      rat3
1  5.553465  4.248335  9.683953  5.949093 11.814671 1.3072098 0.7141147 0.8196549
2  4.989168 19.768138 15.344424  4.553023  5.460138 0.2523843 4.3417611 2.8102630
3  2.563682  3.840026 11.729091  9.765656  2.492230 0.6676210 0.3932174 4.7062635
4  6.987971 17.411003  7.534210 11.211069  1.487920 0.4013537 1.5530190 5.0635854
5 19.220936 17.939368  5.404000  4.085964  8.164280 1.0714389 4.3904861 0.6619077
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