I have this data frame :
Var1 var 2 var3
var1 var2 var3
A B 1
B C 2
B A 3
D C 4
B D 5
And I would like to transform it to a matrix And add a column and a row to sum the values associated to each variable like this using R code:
A B C D Total
A 0 1 0 0 1
B 3 0 2 5 10
C 0 0 0 0 0
D 0 0 4 0 4
T 3 1 6 5
Can you suggest me a way of doing it ?
Thanks a lot!!
nms <- sort(unique(c(as.character(df$var1),as.character(df$var2))));
m <- matrix(vector(typeof(df$var3),1L),length(nms),length(nms),dimnames=list(nms,nms));
m[cbind(as.character(df$var1),as.character(df$var2))] <- df$var3;
m;
## A B C D
## A 0 1 0 0
## B 3 0 2 5
## C 0 0 0 0
## D 0 0 4 0
The as.character() coercions can be omitted if the var1 and var2 input columns are already character vectors.
Data
df <- data.frame(var1=c('A','B','B','D','B'),var2=c('B','C','A','C','D'),var3=c(1L,2L,3L,4L,
5L));
Marginal totals can be added as follows:
m <- cbind(m,Total=rowSums(m));
m <- rbind(m,T=colSums(m));
m;
## A B C D Total
## A 0 1 0 0 1
## B 3 0 2 5 10
## C 0 0 0 0 0
## D 0 0 4 0 4
## T 3 1 6 5 15
