[R] convert data frame of values into correlation matrix

[Juliet Hannah]

Hi Group,

Consider a data frame like this:

mylabel1 <- rep(c("A","B","C"),each=3)
mylabel2 <- rep(c("A","B","C"),3)
corrs <- c(1,.8,.7,.8,1,.7,.7,.7,1)
 myData <- data.frame(mylabel1,mylabel2,corrs)

myData

  mylabel1 mylabel2 corrs
1        A        A   1.0
2        A        B   0.8
3        A        C   0.7
4        B        A   0.8
5        B        B   1.0
6        B        C   0.7
7        C        A   0.7
8        C        B   0.7
9        C        C   1.0

I would like to find a general way to get this matrix from the above dataframe.

corrmat <- matrix(corrs,nrow=3,byrow=TRUE)
row.names(corrmat) <- c("A","B","C")
colnames(corrmat) <- c("A","B","C")
corrmat
    A   B   C
A 1.0 0.8 0.7
B 0.8 1.0 0.7
C 0.7 0.7 1.0

The solution I have is the one above where I rearrange the data so
that I can just use matrix() on one
of the columns. I am looking for a solution in which I don't have to do this.

Thanks,

Juliet