If I want to print the symbol denoting an object in R I can use quote():
如果我想在R中打印表示对象的符号，我可以使用quote（）：
> X <- list()
> print(quote(X))
X
>
However, if I have the function
但是，如果我有这个功能
h <- function(Y){
quote(Y)
}
then
然后
> h(X)
Y
>
Is it possible in R to write a function such that
在R中是否可以编写这样的函数
> h(X)
X
?
？
3 个解决方案
#1
12
> f = function(x) print(deparse(substitute(x)))
> f(asd)
[1] "asd"
>
Why? As you've found out quote() tells R to not evaluate a code block (which it does with Y). substitute() behaves differently; there's a good example at ?substitute.
为什么？正如您所发现的，quote（）告诉R不要评估代码块（它与Y一起）。 substitute（）表现不同;有一个很好的例子吗？替代品。
#2
6
h <- function(x) match.call()[['x']]
h(X)
X
#3
0
substitute also works without the extra calls:
替代也可以没有额外的电话工作：
h <- function(x) substitute(x)
h(X)
X
#1
12
> f = function(x) print(deparse(substitute(x)))
> f(asd)
[1] "asd"
>
Why? As you've found out quote() tells R to not evaluate a code block (which it does with Y). substitute() behaves differently; there's a good example at ?substitute.
为什么？正如您所发现的，quote（）告诉R不要评估代码块（它与Y一起）。 substitute（）表现不同;有一个很好的例子吗？替代品。
#2
6
h <- function(x) match.call()[['x']]
h(X)
X
#3
0
substitute also works without the extra calls:
替代也可以没有额外的电话工作：
h <- function(x) substitute(x)
h(X)
X