我有一个相对容易的问题，我有这个数据框有两个字符对象，称为a和b。像这样：
data<-data.frame(a=c("a","a","a","b","b","c","c","d"),
b=c("x","y","z","y","z","x","z","z"))
如何将此数据帧转换为如下所示的矩阵：
matrix<-matrix( c(1,1,1,0,1,1,1,0,1,0,0,1),nrow=4, ncol=3 )
rownames(matrix)<-c("a","b","c","d")
colnames(matrix)<-c("x","y","z")
我尝试过sapply和lapply的组合，并在线寻找答案但没有成功。
谢谢！ 此致