and thanks in advance for your help. I am very new to R and am having some trouble with code that, to me looks like it should work, but isn't. I have a data frame like the one below:
studentID classNumber classRating
7 1 4
7 2 4
7 4 3
79 1 5
79 2 3
116 1 5
116 2 4
134 1 5
134 3 5
134 4 5
And I want it to read like this:
Student ID class1 class2 class3 class4
7 4 4 NA 3
79 5 3 NA NA
116 5 4 NA NA
134 5 NA 5 5
I've tried to piece together different things that I've come across and it seemed like the best approach was to create a new data frame and matrix and then populate it from the current data frame. I came up with the broken code below:
classRatings = data.frame(matrix(NA,4,5))
for(i in 1:nrow(classDB)){
#Find ratings by each student
rowsToReplace = classDB$studentID==classRatings$studentID[i]
#Make a row for each unique studentID in classRatings
classDB$studentID[rowsToReplace] = classRatings$studentID[i]
#for each studentID, find put the given rating for each unique class into
#it's own vector
for(j in classDB$classNumber){
if(classDB$classNumber==1){classRatings$class1==classDB$classRating}[j]
if(classDB$classNumber==2){classRatings$class2==classDB$classRating}[j]
if(classDB$classNumber==3){classRatings$class3==classDB$classRating}[j]
if(classDB$classNumber==4){classRatings$class4==classDB$classRating}[j]
if(classDB$classNumber==5){classRatings$class5==classDB$classRating}[j]
}
}
I'm getting an error that says:
the condition has length > 1 and only the first element will be used
and I am beyond my skill level to figure it out. Any help is appreciated.
The tidyr package can spread this long table into a wider one:
library(tidyr)
spread(classDB,classNumber,classRating,fill=NA)
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