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Ciao, I have two columns. Every row represents one student. The first column tells what class the student is in. The second column tells if the student passed a exam.

Here is my replicating example. This is the data I have now:

a=c("A","A","A","A","B","B","B","C","C")
b=c(0,0,1,0,0,0,0,1,1)
mydata=data.frame(a,b)
names(mydata)=c("CLASS","PASSED")

This is the data I seek to attain:

a1=c("A","B","C")
b1=c(4,3,2)
c1=c(1,0,2)
mydataWANT=data.frame(a1,b1,c1)
names(mydataWANT)=c("CLASS","SIZE","PASSED")

Here is my attempt for the dplyr package

mydataWANT <- data.frame(mydata %>% 
  group_by(CLASS,PASSED) %>%
  summarise(N = n()))

yet it does not yield the desire output.

bvowe
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    So close.... `mydata %>% group_by(CLASS) %>% summarise(N = n(), Passed = sum(PASSED))` No need to group by `Passed` because you need that for your calculations. – AntoniosK Aug 29 '18 at 15:32

0 Answers0