1 message()函数

可以使用message()函数进行终端屏幕输出.

message("ABC", "DEF")

## ABCDEF

suppressMessages(message("ABC"))

testit <- function() {
  message("testing package startup messages")
  packageStartupMessage("initializing ...", appendLF = FALSE)
  Sys.sleep(1)
  packageStartupMessage(" done")
}

testit()

## testing package startup messages

## initializing ... done

suppressPackageStartupMessages(testit())

## testing package startup messages

suppressMessages(testit())

2 改变输出字体颜色和格式

使用crayon包可以修改输出字体的颜色.参考官方文档:https://github.com/r-lib/crayon.

library(crayon)

## Warning: package 'crayon' was built under R version 3.6.1

cat(blue("Hello", "world!\n"))

## Hello world!

cat("... to highlight the " %+% red("search term") %+% " in a block of text\n")

## ... to highlight the search term in a block of text

cat(yellow$bgMagenta$bold('Hello world!\n'))

## Hello world!

cat(green(
  'I am a green line ' %+%
  blue$underline$bold('with a blue substring') %+%
  ' that becomes green again!\n'
))

## I am a green line with a blue substring that becomes green again!

error <- red $ bold
warn <- magenta $ underline
note <- cyan
cat(error("Error: subscript out of bounds!\n"))

## Error: subscript out of bounds!

cat(warn("Warning: shorter argument was recycled.\n"))

## Warning: shorter argument was recycled.

cat(note("Note: no such directory.\n"))

## Note: no such directory.

3 一些常用的特殊字符

使用clisymbols包可以给出一些常见的特殊字符.

官方文档:https://github.com/r-lib/clisymbols.

library(clisymbols)
cat(symbol$tick, "All good\n")

## <U+2714> All good

cat(symbol$cross, "Problem\n")

## <U+2716> Problem

for (i in seq_along(symbol)) {
  cat(symbol[[i]], "\t", names(symbol)[i], "\n", sep = "")
}

## <U+2714> tick
## <U+2716> cross
## <U+2605> star
## <U+2587> square
## [ ]  square_small
## [¦]  square_small_filled
## <U+25EF> circle
## (*)  circle_filled
## <U+25CC> circle_dotted
## (o)  circle_double
## <U+24DE> circle_circle
## <U+24E7> circle_cross
## <U+24BE> circle_pipe
## (?)  circle_question_mark
## <U+25CF> bullet
## .    dot
## -    line
## -    double_line
## …    ellipsis
## >    pointer
## i    info
## <U+203C> warning
## <U+2630> menu
## <U+263A> smiley
## <U+0DF4> mustache
## <U+2665> heart
## <U+2191> arrow_up
## <U+2193> arrow_down
## <U+2190> arrow_left
## <U+2192> arrow_right
## (*)  radio_on
## ( )  radio_off
## <U+2612> checkbox_on
## <U+2610> checkbox_off
## <U+24E7> checkbox_circle_on
## <U+24BE> checkbox_circle_off
## (?)  fancy_question_mark
## !=   neq
## >=   geq
## <=   leq
## <U+2594> upper_block_1
## ¯    upper_block_4
## <U+2581> lower_block_1
## <U+2582> lower_block_2
## <U+2583> lower_block_3
## _    lower_block_4
## <U+2585> lower_block_5
## <U+2586> lower_block_6
## <U+2587> lower_block_7
## ¦    lower_block_8
## ¦    full_block