正则表达式：替换两个字符之间的所有空格

Question

考虑以下字符串： This is an example: this is another one, and this is yet another, and other, and so on.字符串， This is an example: this is another one, and this is yet another, and other, and so on.字符串This is an example: this is another one, and this is yet another, and other, and so on. 我想替换:和,之间的所有空格字符。 所以它看起来像这样This is an example:_this_is_another_one, and this is yet another, and other, and so on.

到目前为止我尝试过的：

• (?<=:)\\s+(?=[^,]*,) （只匹配第一个空格）
• :\\s+(?=[^:,]*,) （同上）
• \\s+(?=[^:,]*,) （匹配This is an example:_this_is_another_one,_and_this_is_yet_another,_and_other, and so on ）

Answer 1

更新：有一种简单的方法可以使用stringr::str_replace_all使用匿名函数作为替换参数来替换 R 中任意字符串之间的任何内容：

通用stringr方法

library(stringr)

# left - left boundary
# right - right boundary
# x - input
# what - regex pattern to search for inside matches
# repl - replacement text for the in-pattern matches
ReplacePatternBetweenTwoStrings <- function(left, right, x, what, repl) {
  left  <- gsub("([][{}()+*^${|\\\\?.])", "\\\\\\1", left)
  right <- gsub("([][{}()+*^${|\\\\?.])", "\\\\\\1", right)
  str_replace_all(x, 
     paste0("(?s)(?<=", left, ").*?(?=", right, ")"),
     function(z) gsub(what, repl, z)
  )
}

x <- "This is an example: this is another one, and this is yet another, and other, and so on."
ReplacePatternBetweenTwoStrings(":", ",", x, "\\s+", "_")
## => [1] "This is an example:_this_is_another_one, and this is yet another, and other, and so on."

请参阅此 R 演示。

替换最近的:和 之间的所有空格,

这是上面的一个简单的边缘情况，当:[^:,]+,匹配 a : ，然后是除:和, （分隔符字符）之外的任意数量的字符，然后是 a , ，然后空格被替换为下划线仅比赛：

stringr::str_replace_all(x, ":[^:,]+,", function(z) gsub("\\s+", "_", z))

查看正则表达式演示

原始答案（比例相当差）

您可以使用以下正则表达式：

(?:\G(?!^)|:)[^,]*?\K\s(?=[^,]*,)

替换为_ 。 请参阅正则表达式演示。

详情

• (?:\\G(?!^)|:) - 前一个匹配的结尾（ \\G(?!)^ ）或冒号
• [^,]*? - 除 之外的任何 0+ 个字符,尽可能少
• \\K - 匹配重置运算符丢弃到目前为止匹配的文本
• \\s - 一个空格
• (?=[^,]*,) - 一个积极的前瞻检查，确保在零个或多个除逗号之外的字符之后有一个, 。

R演示：

re <- "(?:\\G(?!^)|:)[^,]*?\\K\\s(?=[^,]*,)"
x <- "This is an example: this is another one, and this is yet another, and other, and so on."
gsub(re, "_", x, perl=TRUE)
# => [1] "This is an example:_this_is_another_one, and this is yet another, and other, and so on."

Answer 2

这是一个略显粗糙的答案：

txt="This is an example: this is another one, and this is yet"

split_str=unlist(strsplit(gsub("^(.*:)(.*)(,.*)", "\\1$\\2$\\3", txt), split="$", fixed=T))

paste0(split_str[1], gsub(" ", "_",split_str[2]), split_str[3])