How to rewrite for-loop using apply function

Question

I have the following data:

rand.sum <- function(n){
x <- sort(runif(n-1))
c(x,1) - c(0,x)
}

M <- t(replicate(8,rand.sum(8))) # data frame with probabilities

Test1 <- as.data.frame(t(replicate(1, rand.sum(8))))
Test2 <- as.data.frame(t(replicate(1, rand.sum(8))))
Test <- rbind(Test1,Test2) # Test data

ID1 <- c("ID1")
ID2 <- c("ID2")
ID <- rbind(ID1,ID2) #ID's

data <- cbind(ID,Test)

Now with the help of the awesome Community I have the following apply function:

gemeinden_new <- lapply(1:dim(Test)[1], function(z)
                   as.data.frame(
                         matrix(sapply(1:8, function(i) sum(data[z,2:9] * M[,i])),
                                nrow=1, ncol=8)
                   ))

Now I want to add a new column and fill it based with data from the df "data".

I have come up with the following solution:

library(tibble)

gemeinden_new <- lapply(gemeinden_new, function(x){
                add_column(x, gemeindeschluessel = 0, .before = 1)
                 })

for(i in 1:dim(Test)[1]) { 
  z <- i
  gemeindeschluessel <- paste(data[z,1])
  gemeinden_new[[z]][z,1] <- gemeindeschluessel
}

While this works it is not very elegant and because I am working with a large dataset I would like to work around for-loops. Is there any possibility to re-write the for-loop using lapply? I was not able to do so.

The final list solution should look like this:

 # $ID1
    #    gemeindeschluessel      V1        V2         V3        V4         V5             V6         V7       V8
    # 1 ID1 0.0598796 0.1526457 0.08604147 0.2314867 0.06307882 0.2047462 0.07962943 0.122492

# $ID2
#    gemeindeschluessel      V1        V2         V3        V4         V5        V6         V7        V8
# 1 ID2 0.1385492 0.1047066 0.06278719 0.1710685 0.09209054 0.2519348 0.06434532 0.1145178

Possible duplicate of [How to put an apply equivalent to any for loop](https://stackoverflow.com/questions/17007526/how-to-put-an-apply-equivalent-to-any-for-loop) — camille, May 01 '18 at 17:11
I'm going to jump in here to say that using an `apply` function will not be any faster than writing an equivalent `for` loop. The reason to use an `apply` function is simply that it allows for clean, easy to read code, for certain applications. More references: https://stackoverflow.com/a/42440872/4421870 — Mako212, May 01 '18 at 20:53
And more on this topic here: https://stackoverflow.com/a/2276001/4421870 — Mako212, May 01 '18 at 20:54

How to rewrite for-loop using apply function

0 Answers0