R: How do I check increasing/decreasing value from different column

Question

How do I check if the student have achieve higher marks in "Grade2" compared to their previous grade in "Grade1"

df = data.frame(Grade1 = c("5","1","7","6"), 
            Grade2 = c("4", "5", "10", "10"))
df

rownames(df) = c("StudentA","StudentB","StudentC","StudentD")
df

Answer 1

Make sure you fix you dataframe to contain integers and not strings.

This will work:

df = data.frame(Grade1 = c(5,1,7,6), 
                Grade2 = c(4, 5, 10, 10))

rownames(df) = c("StudentA","StudentB","StudentC","StudentD")

mask <- df$Grade2 > df$Grade1
rownames(df[mask,])

Output:

[1] "StudentB" "StudentC" "StudentD"