[R] Why strsplit can be used with matrix but not data.frame?

[Peng Yu]

Hi,

As show in the code below, strsplit can be applied to a matrix but not
a data.frame. I don't understand why R is designed in this way. Can
somebody help me understand it? How to split all the strings in x$y?

x=data.frame(x=1:10,y=rep("abc",10))
strsplit(x$y,'b') #Error in strsplit(x$y, "b") : non-character argument
y=cbind(1:10,rep("abc",10))
strsplit(y[,2],'b')

Regards,
Peng