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如何格式化多行R包消息?

message format string r

nsheff · 技术社区 · 7 年前

R 的 message() 或 warning() 函数为我的包用户生成输出。

message("If you got to this point in the code, it means the matrix was empty. Calculation continues but you should consider re-evaluating an earlier step in the process")

太棒了但对于风格,我也希望 代码行少于80个字符 ,因此它们非常适合窄屏幕、GitHub等。然后,如果消息发生变化,我可以使用IDE代码回流工具轻松地重新格式化消息。

所以我试着这样做:

message("If you got to this point in the code, it means 
the matrix was empty. Calculation continues but you should consider
 re-evaluating an earlier step in the process")

这解决了我的代码标准——少于80个字符行,可以按预期回流。但这会在我的消息输出中留下空白,我也不希望这样:

If you got to this point in the code, it means 
the matrix was empty. Calculation continues but you should consider
 re-evaluating an earlier step in the process

所以我找到了一个方便的函数,叫做 strwrap() 这似乎解决了问题:

message(strwrap("If you got to this point in the code, it means 
the matrix was empty. Calculation continues but you should consider
 re-evaluating an earlier step in the process"))

If you got to this point in the code, it means the matrix was empty. 
Calculation continues but you should considerre-evaluating an earlier 
step in the process

看起来不错——但它消除了“考虑”和“重新评估”之间的空间,因为该空间位于新线。

另一种选择是在代码中将其分解成块:

message("If you got to this point in the code, it means ", 
"the matrix was empty. Calculation continues but you should consider ",
"re-evaluating an earlier step in the process")

这使输出看起来正确,但文本不能再轻易地用IDE等回流,因为它不是一个字符串,所以这在开发端对我不起作用。

那么:我如何制作一个格式良好的消息,让我可以轻松地跨行书写消息?

我编写了这个函数:

.nicemsg = function(...) {
    message(paste(strwrap(...), collapse="\n"))
}

2 回复 | 直到 7 年前

Benjamin 7 年前

使用来自 strwrap 使这成为可能

message(strwrap(..., prefix = " ", initial = ""))

您可以通过调整参数顺序来提高可读性。我不确定这是否更好。

message(strwrap(prefix = " ", initial = "", 
  "If you got to this point in the code, it means 
the matrix was empty. Calculation continues but you should consider
 re-evaluating an earlier step in the process"))

或者,如果你喜欢包装它

tidymess <- function(..., prefix = " ", initial = ""){
  message(strwrap(..., prefix = prefix, initial = initial))
}

-3

Andrew BrÄza 7 年前

\n 在字符串中。

message("If you got to this point in the code,\nit means the matrix was empty.\nCalculation continues but you should consider re-evaluating\nan earlier step in the process")
# If you got to this point in the code,
# it means the matrix was empty.
# Calculation continues but you should consider re-evaluating
# an earlier step in the process