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How to find the total number of rows per group combination in an R data frame?
An R data frame that contains two or more factor columns then there are a greater number of combinations for the number of factors, obviously, if the number of factors is large with large number of levels then the combination of levels of the factors is also large. To find total number of rows per group combination we can use transform function.
Example
Consider the below data frame −
set.seed(101) Group<-rep(c("G1","G2","G3","G4","G5"),times=4) Class<-rep(c("A","B","C"),times=c(8,7,5)) Frequency<-sample(1:100,20) df<-data.frame(Group,Class,Frequency) df
Output
Group Class Frequency 1 G1 A 73 2 G2 A 57 3 G3 A 46 4 G4 A 95 5 G5 A 81 6 G1 A 58 7 G2 A 61 8 G3 A 60 9 G4 B 59 10 G5 B 3 11 G1 B 32 12 G2 B 9 13 G3 B 31 14 G4 B 93 15 G5 B 53 16 G1 C 92 17 G2 C 49 18 G3 C 14 19 G4 C 76 20 G5 C 45
Example
transform(df,Total=ave(Frequency,Group,Class, FUN = length))
Output
Group Class Frequency Total 1 G1 A 73 2 2 G2 A 57 2 3 G3 A 46 2 4 G4 A 95 1 5 G5 A 81 1 6 G1 A 58 2 7 G2 A 61 2 8 G3 A 60 2 9 G4 B 59 2 10 G5 B 3 2 11 G1 B 32 1 12 G2 B 9 1 13 G3 B 31 1 14 G4 B 93 2 15 G5 B 53 2 16 G1 C 92 1 17 G2 C 49 1 18 G3 C 14 1 19 G4 C 76 1 20 G5 C 45 1
Let’s have a look at another example with similar data −
Example
set.seed(101) Group<-rep(c("G1","G2"),times=10) Class<-rep(c("A","B","C"),times=c(8,7,5)) df2<-data.frame(Group,Class,Frequency) set.seed(101) Group<-rep(c("G1","G2"),times=10) Class<-rep(c("A","B","C"),times=c(8,7,5)) Frequency<-sample(1:100,20) df2<-data.frame(Group,Class,Frequency) df2
Output
Group Class Frequency 1 G1 A 73 2 G2 A 57 3 G1 A 46 4 G2 A 95 5 G1 A 81 6 G2 A 58 7 G1 A 61 8 G2 A 60 9 G1 B 59 10 G2 B 3 11 G1 B 32 12 G2 B 9 13 G1 B 31 14 G2 B 93 15 G1 B 53 16 G2 C 92 17 G1 C 49 18 G2 C 14 19 G1 C 76 20 G2 C 45
Example
transform(df2,Total=ave(Frequency,Group,Class, FUN = length))
Output
Group Class Frequency Total 1 G1 A 73 4 2 G2 A 57 4 3 G1 A 46 4 4 G2 A 95 4 5 G1 A 81 4 6 G2 A 58 4 7 G1 A 61 4 8 G2 A 60 4 9 G1 B 59 4 10 G2 B 3 3 11 G1 B 32 4 12 G2 B 9 3 13 G1 B 31 4 14 G2 B 93 3 15 G1 B 53 4 16 G2 C 92 3 17 G1 C 49 2 18 G2 C 14 3 19 G1 C 76 2 20 G2 C 45 3
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