在 R 中使用 print() 打印换行符

发布于11月02日

我正在try 用R打印多行消息.例如，

print("File not supplied.\nUsage: ./program F=filename",quote=0)

我得到了输出

File not supplied.\nUsage: ./program F=filename

而不是想要的

File not supplied.
Usage: ./program F=filename

推荐答案

cat()的替代方案是writeLines():

> writeLines("File not supplied.\nUsage: ./program F=filename")
File not supplied.
Usage: ./program F=filename
>

一个优点是，您不必记住在传递到cat()的字符串后面附加"\n"，就可以在消息后面获得换行符.例如，将上述结果与相同的cat()输出进行比较:

> cat("File not supplied.\nUsage: ./program F=filename")
File not supplied.
Usage: ./program F=filename>

和

> cat("File not supplied.\nUsage: ./program F=filename","\n")
File not supplied.
Usage: ./program F=filename
>

The reason print() doesn't do what you want is that print() shows you a version of the object from the R level - in this case it is a character string. You need to use other functions like cat() 和 writeLines() to display the string. I say "a version" because precision may be reduced in printed numerics, 和 the printed object may be augmented with extra information, for example.