从print()控制台输出重新创建矢量

Question

遗憾的是,您经常会看到有关SO的问题,这些问题以不可复制的格式呈现数据; 往往只是复制的结果print()...

set.seed(1)

x <- sample(LETTERS, 40, replace = T)
y <- rnorm(20)

......比如这样:

x
 [1] "G" "J" "O" "X" "F" "X" "Y" "R" "Q" "B" "F" "E" "R" "J" "U" "M" "S"
[18] "Z" "J" "U" "Y" "F" "Q" "D" "G" "K" "A" "J" "W" "I" "M" "P" "M" "E"
[35] "V" "R" "U" "C" "S" "K"

... 或这个:

y
 [1]  0.91897737  0.78213630  0.07456498 -1.98935170  0.61982575
 [6] -0.05612874 -0.15579551 -1.47075238 -0.47815006  0.41794156
[11]  1.35867955 -0.10278773  0.38767161 -0.05380504 -1.37705956
[16] -0.41499456 -0.39428995 -0.05931340  1.10002537  0.76317575

理想情况下,我希望能够将上面的块中的文本复制到我的剪贴板,并调用一些函数foo(),以便all.equal(foo(), x)对离散数据类型和all(near(foo(), y))浮点数(给定打印精度).

是否有一种简单的方法(大致)从复制的结果中重建一个简单的向量print()？

---

编辑:具有讽刺意味的是,我意识到我自己的例子并不完全可以完全重现.这是创建复制的打印输出的代码:

y_printed <- capture.output(y)

Answer 1

我用scan这个问题。

你能用下面的代码创建一个函数吗？

y <-
  '[1]  0.91897737  0.78213630  0.07456498 -1.98935170  0.61982575
 [6] -0.05612874 -0.15579551 -1.47075238 -0.47815006  0.41794156
[11]  1.35867955 -0.10278773  0.38767161 -0.05380504 -1.37705956
[16] -0.41499456 -0.39428995 -0.05931340  1.10002537  0.76317575'

y <- scan(what = character(), text = y)
y <- sub("^\\s*\\[\\d+\\]", "", y)
y <- as.numeric(y[y != ""])

根据@Moody_Mudskipper 评论中的建议，

模式可以更新为“^\s*\[\d+\]”以支持OP的示例（以空格开头）。

一个函数可以是

recreateVector <- function(X, numeric = TRUE, quiet = FALSE){
  X <- scan(what = character(), text = X, quiet = quiet)
  X <- sub("^\\s*\\[\\d+\\]", "", X)
  X <- X[X != ""]
  if(numeric) X <- as.numeric(X)
  X
}


recreateVector(y)   # Use the original y
#Read 24 items
# [1]  0.91897737  0.78213630  0.07456498 -1.98935170  0.61982575
# [6] -0.05612874 -0.15579551 -1.47075238 -0.47815006  0.41794156
#[11]  1.35867955 -0.10278773  0.38767161 -0.05380504 -1.37705956
#[16] -0.41499456 -0.39428995 -0.05931340  1.10002537  0.76317575

对于字符向量，设置参数numeric = FALSE，默认值为TRUE。

x <-
'[1] "G" "J" "O" "X" "F" "X" "Y" "R" "Q" "B" "F" "E" "R" "J" "U" "M" "S"
[18] "Z" "J" "U" "Y" "F" "Q" "D" "G" "K" "A" "J" "W" "I" "M" "P" "M" "E"
[35] "V" "R" "U" "C" "S" "K"'

recreateVector(x, numeric = FALSE)
#Read 43 items
# [1] "G" "J" "O" "X" "F" "X" "Y" "R" "Q" "B" "F" "E" "R" "J" "U"
#[16] "M" "S" "Z" "J" "U" "Y" "F" "Q" "D" "G" "K" "A" "J" "W" "I"
#[31] "M" "P" "M" "E" "V" "R" "U" "C" "S" "K"

注意论证quiet。我已将默认值设置为FALSE，就像在 的定义中一样scan，因为我更喜欢查看是否实际读入了任何内容。