r - 函数的多行 comment() 属性

Question

假设我有以下功能:

sqrt_x = function(x) {
     sqrtx = x^0.5
     return(list("sqrtx" = sqrt))
}  
attr(sqrt_x, "comment") <- "This is a comment to be placed on two different lines"

如果我输入

comment(sqrt_x) 

我明白了

[1] "This is a comment to be placed on two different lines"

然而，我想要的是评论在两行不同的行上返回(它也可以是更多行和不同的评论元素。任何想法都值得赞赏。

Answer 1

正如 Andrie 所说:您需要插入换行符。

如果您不想手动指定换行符的位置，那么您可以使用 strwrap 在方便的位置创建中断，这样您的字符串就不会超过指定的宽度。

msg <- strwrap("This is a comment to be placed on two different lines", width = 20)
cat(msg, sep = "\n")
# This is a comment
# to be placed on two
# different lines

---

完整的解决方案可能类似于:

#Add comment as normal
comment(sqrt_x) <- "This is a comment to be placed on two different lines"

#Display using this function
multiline_comment <- function(x, width = getOption("width") - 1L)
{
  cat(strwrap(comment(x), width = width), sep = "\n")
}

multiline_comment(
  sqrt_x, 
  20
)