readLines未知n

Question

在gui中(无论是Windows还是RStudio等)，我可以通过指定readLines来使用脚本中的已知行数，如下面所示。如果我不确定正在读的行数(也就是说，我有很多行而不知道n)，该怎么办？如何在gui中使用readLines (从外部文件中的脚本读取)而不指定n？如果不提供n，则readLines将保持连接打开，并继续读行。点击esc会停止这个功能，但是没有读取任何行。

x <- readLines(n=4)
** preparing package for lazy loading
** help
*** installing help indices
** building package indices

x

这是一段视频演示了我要问的具体问题。

当海报以如下所示的奇怪格式给出数据时，并且您想在不计算所有行的情况下读取数据时，这一点尤其有用：

** preparing package for lazy loading
** help
*** installing help indices
** building package indices
** preparing package for lazy loading
** help
*** installing help indices
** building package indices
** preparing package for lazy loading
** help
*** installing help indices
** building package indices
** preparing package for lazy loading
** help
*** installing help indices
** building package indices
** preparing package for lazy loading
** help
*** installing help indices
** building package indices

编辑，直到这个被重新打开，Dason可以自己回答.

Dason建议使用ctrl +z，这是可行的(至少在Windows机器上是如此)

Answer 1

两个简单的解决方案。

1. 将文本放入另一个文件中，并读取该文件。
2. 不要使用readLines。引用案文：

​

x <- strsplit("** preparing package for lazy loading
** help
*** installing help indices
** building package indices
", "\n")


x
[[1]]
[1] "** preparing package for lazy loading" "** help"                               "*** installing help indices"          
[4] "** building package indices"          

Answer 2

您可以将引号环绕在文本周围，并创建要读取的textConnection。

text <- "** preparing package for lazy loading
** help
*** installing help indices
** building package indices
** preparing package for lazy loading
** help
*** installing help indices
** building package indices
** preparing package for lazy loading
** help
*** installing help indices
** building package indices
** preparing package for lazy loading
** help
*** installing help indices
** building package indices
** preparing package for lazy loading
** help
*** installing help indices
** building package indices"

readLines(textConnection(text))
# [1] "** preparing package for lazy loading" "** help"                              
# [3] "*** installing help indices"           "** building package indices"          
# [5] "** preparing package for lazy loading" "** help"                              
# [7] "*** installing help indices"           "** building package indices"          
# [9] "** preparing package for lazy loading" "** help"                              
#[11] "*** installing help indices"           "** building package indices"          
#[13] "** preparing package for lazy loading" "** help"                              
#[15] "*** installing help indices"           "** building package indices"          
#[17] "** preparing package for lazy loading" "** help"                              
#[19] "*** installing help indices"           "** building package indices"  

Answer 3

在Windows环境中，选择并复制到剪贴板后：

 (clip.input <- readLines( file("clipboard") ) )

在Mac/UNIX中：

 (clip.input <- readLines( pipe("pbpaste") ) )