如何在R中使用带有变量的函数？

Question

in R,the pdf function can save graph in c:/test :

pdf("c:/test")

I want to make a variable substitue pdf ,how can i make it run ?

str<-"pdf"
str("c:/test")

Answer 1

get（）这样做：

get(str)("c:/test")

Answer 2

s = "pdf" ; do.call(s, list("c:/test"))

or in two steps,

cl <- call(s, "c:/test")
eval(cl)

Answer 3

You can extract the function specified by the name in str with match.fun :

match.fun(str)("c:/test")

By the way: It is not a good idea to name an object str since this is the name of a basic function in R.