解决方案不是很相似吗?

Isn't the solution pretty similar?

x <- c("a,b,c", ",a,b,,c", ",,,a,,,b,c,,,")
gsub("^,*|(?<=,),|,*$", "", x, perl=T)
# [1] "a,b,c" "a,b,c" "a,b,c"

正则表达式^,*|(?<=,),|,*$分为三个部分:

There are three parts to the regex ^,*|(?<=,),|,*$:

• ^,*-匹配字符串开头的0个或多个逗号
• (?<=,),-这是正向后看，以查看是否有逗号在逗号后面，因此它与,,
中的,相匹配
• ,*$-匹配字符串末尾的0个或多个逗号

• ^,* -- this matches 0 or more commas at the beginning of the string
• (?<=,), -- this is a positive lookbehind to see if there a comma behind a comma, so it matches , in ,,
• ,*$ -- this matches 0 or more commas at the end of the string

如您所见，以上所有内容均被替换为空.

As you can see all of the above are substituted with nothing.

您可以使用以下功能将此通用名称应用于任何字符(" "，","等):

You can make this generic to any character (" ", ",", etc.) with this function:

TrimMult <- function(x, char=" ") {
  return(gsub(paste0("^", char, "*|(?<=", char, ")", char, "|", char, "*$"),
              "", x, perl=T))
}