在 R 中，如何选择和应用函数向量的元素？
我有一个 R 问题——我想创建一个函数向量，然后能够通过名称调用其中一个函数。但是，当我使用这个名称时，我想使用一个映射到该名称的标签，这样我就可以选择使用哪个名称，而无需更改代码。例如：
#define tag
tag<-"F"
#define functions
f <- function(x) print(x^2)
g <- function(x) print(x^3)
#define vector
fs<-c(f,g)
names(fs)<-c("F", "G")
#create input data
x<-5
fs$F(x)
#this gives the desired output but I want to use tag
#that is, I want syntax which uses tag, so that which element I use from fs is flexible until tag is defined
#e.g. I had hoped the following would work, but it doesn't
fs[tag](x)
有什么建议吗？
I have an R question--I want to make a vector of functions, and then be able to call one of the functions by name. However, when I use this name, I want to use a tag which maps to that name, so that I can chance which name I use without having to change the code. For example:
#define tag
tag<-"F"
#define functions
f <- function(x) print(x^2)
g <- function(x) print(x^3)
#define vector
fs<-c(f,g)
names(fs)<-c("F", "G")
#create input data
x<-5
fs$F(x)
#this gives the desired output but I want to use tag
#that is, I want syntax which uses tag, so that which element I use from fs is flexible until tag is defined
#e.g. I had hoped the following would work, but it doesn't
fs[tag](x)
Any suggestions?
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使用这部分代码，
您创建了一个列表（尝试
class (fs)或str (fs)），因此最后一行的索引必须更改为：
只需稍微研究一下索引即可了解结构。
（例如查看
fs、fs[1]、fs[[1]]等等）with this part of your code
you have created a list (try
class (fs)orstr (fs))therefore the indexing of you last line has to be changed to:
just play a bit around with the indexes to get a feeling for the structure.
(eg look at
fs,fs[1],fs[[1]]and so forth)