Question

我正在尝试将月份名称合并到存储变量的名称中。

import <- function(month) {
  dataobj <- letters
  assign("x", dataobj)
  save("x", file="data.rda")
}

的工作原理。但以下不起作用 -

import <- function(month) {
  dataobj <- letters
  assign(substr(month, 1, 3), dataobj)
  save(substr(month, 1, 3), file="data.rda")
}

似乎 save（）将接受“x”但不接受 substr（month，1,3）。

任何想法如何解决这个问题？

Answer 1

使用list的{{1}}参数：

save()

Answer 2

我不会使用特定的，依赖于月份的名称在环境中创建对象，而是使用month作为名称的对象列表。

dat = lapply(1:4, function(x) letters)
names(dat) = c("Jan","Feb","Mar","Apr")
> dat
$Jan
 [1] "a" "b" "c" "d" "e" "f" "g" "h" "i" "j" "k" "l" "m" "n" "o" "p" "q" "r" "s" 
[20] "t" "u" "v" "w" "x" "y" "z"                                                 

$Feb                                                                             
 [1] "a" "b" "c" "d" "e" "f" "g" "h" "i" "j" "k" "l" "m" "n" "o" "p" "q" "r" "s" 
[20] "t" "u" "v" "w" "x" "y" "z"                                                 

$Mar                                                                             
 [1] "a" "b" "c" "d" "e" "f" "g" "h" "i" "j" "k" "l" "m" "n" "o" "p" "q" "r" "s" 
[20] "t" "u" "v" "w" "x" "y" "z"                                                 

$Apr                                                                             
 [1] "a" "b" "c" "d" "e" "f" "g" "h" "i" "j" "k" "l" "m" "n" "o" "p" "q" "r" "s" 
[20] "t" "u" "v" "w" "x" "y" "z"

使用save(dat)可以轻松保存此列表。如果您热衷于将月份保存在单独的对象中：

lapply(names(dat), function(month) {
  save(dat[[month]], file = sprintf("%s.rda", month)
 })

或使用旧的for循环：

for(month in names(dat)) {
  save(dat[[month]], file = sprintf("%s.rda", month)
}

在R中的函数内使用参数作为变量名

2 个答案: