如何删除前导空格

Question

我不熟悉R中的文本处理,并坚持如何删除字符串中的前导空格.这是一些代码:

set.seed(1234)
b <- paste0(sample(c("bbb ", " bbb "), 10, replace = TRUE), rep("ccc ddd", 10))
print(b)

 [1] "bbb ccc ddd"  " bbb ccc ddd" " bbb ccc ddd" " bbb ccc ddd" " bbb ccc ddd"
 [6] " bbb ccc ddd" "bbb ccc ddd"  "bbb ccc ddd"  " bbb ccc ddd" " bbb ccc ddd"

我发现我可以删除尾随空白sub(' +$', '', b)但是将其更改为sub ('$+ ', '', b)不会删除前导空格.猜猜这是一个快速解决方案......

Answer 1

尝试str_trim从stringr.

对于左侧

> library(stringr)
> str_trim(b, "left")
# [1] "bbb ccc ddd" "bbb ccc ddd" "bbb ccc ddd" "bbb ccc ddd" "bbb ccc ddd"
# [6] "bbb ccc ddd" "bbb ccc ddd" "bbb ccc ddd" "bbb ccc ddd" "bbb ccc ddd"

同样,str_trim(b, "right")对于右侧.对于双方来说,简单而言 str_trim(b)