# create a dataframe with 4 columns
data = data.frame(subjects=c("java", "python", "java",
"java", "php", "php"),
id=c(1, 2, 3, 4, 5, 6),
names=c("manoj", "sai", "mounika",
"durga", "deepika", "roshan"),
marks=c(89, 89, 76, 89, 90, 67))
# display
print(data)
# aggregate sum of marks with subjects
print(aggregate(data$marks, list(data$subjects), FUN=sum))
# aggregate minimum of marks with subjects
print(aggregate(data$marks, list(data$subjects), FUN=min))
# aggregate maximum of marks with subjects
print(aggregate(data$marks, list(data$subjects), FUN=max))