I have a dataframe that looks like this:
df <- data.frame(Subject = c(rep("A", 6), rep("B", 6)),
Trial = c(rep(c(rep(1, 2), rep(2, 2), rep(3, 2)), 2)),
Feature_1 = c(rep(123, 2), rep(234, 2), rep(345, 2), rep(456, 2), rep(567, 2), rep(678, 2)),
Feature_2 = c(rep(321, 2), rep(543, 2), rep(654, 2), rep(765, 2), rep(876, 2), rep(987, 2)),
Feature_3 = c(rep(190, 2), rep(459, 2), rep(392, 2), rep(398, 2), rep(492, 2), rep(587, 2)),
Feature_correct = NA)
df
Subject Trial Feature_1 Feature_2 Feature_3 Feature_correct
1 A 1 123 321 190 NA
2 A 1 123 321 190 NA
3 A 2 234 543 459 NA
4 A 2 234 543 459 NA
5 A 3 345 654 392 NA
6 A 3 345 654 392 NA
7 B 1 456 765 398 NA
8 B 1 456 765 398 NA
9 B 2 567 876 492 NA
10 B 2 567 876 492 NA
11 B 3 678 987 587 NA
12 B 3 678 987 587 NA
What I need is for the Feature_correct column to contain the values from Feature_n depending on Trial for each Subject. So, for Subject A & Trial 1, Feature_correct should have the values corresponding to Subject A & Trial 1 under Feature_1. For Subject A & Trial 2, Feature_correct should have the values corresponding to Subject A & Trial 2 under Feature_2, and so on.
This is my goal:
df$Feature_goal <- c(rep(123, 2), rep(543, 2), rep(392, 2), rep(456, 2), rep(876, 2), rep(587, 2))
head(df)
Subject Trial Feature_1 Feature_2 Feature_3 Feature_correct Feature_goal
1 A 1 123 321 190 NA 123
2 A 1 123 321 190 NA 123
3 A 2 234 543 459 NA 543
4 A 2 234 543 459 NA 543
5 A 3 345 654 392 NA 392
6 A 3 345 654 392 NA 392
I know how to do this manually (specifying the Subject name and Trial number in the syntax), but I'd like to create a loop (or whatever else works) so that I don't have to type the name of each Subject (in my real dataset I have many participants and many "Feature" variables).
I've tried this for loop, but I get an error:
df <- for(i in 1:nrow(df$Subject)) {
if(df$Trial %in% 1){
df[df$Subject == i & df$Trial %in% 1,]$Feature_correct = df[df$Subject == i & df$Trial %in% 1,]$Feature_1
}
if(df$Trial %in% 2){
df[df$Subject == i & df$Trial %in% 2,]$Feature_correct = df[df$Subject == i & df$Trial %in% 2,]$Feature_2
}
if(df$Trial %in% 3){
df[df$Subject == i & df$Trial %in% 3,]$Feature_correct = df[df$Subject == i & df$Trial %in% 3,]$Feature_3
}
}
> Error in 1:nrow(df$Subject) : argument of length 0
Indeed,
nrow(df$Subject)
> NULL
Would anyone know how to make this work (with the loop or in any other way)?
