Question

是否可以使用在URL字符串末尾忽略某些标点符号（而不是＆＃34; /＆＃34;）的正则表达式函数（即网址末尾的标点符号）提取后的字符串后跟一个空格？在提取网址时，我会在我提取的字符串末尾获取句点，括号，问号和感叹号，例如：

findURL <- function(x){
  m <- gregexpr("http[^[:space:]]+", x, perl=TRUE)
  w <- unlist(regmatches(x,m))
  op <- paste(w,collapse=" ")
  return(op)
}

x <- "find out more at http://bit.ly/SS/VUEr). check it out here http://bit.ly/14pwinr)? http://bit.ly/108vJOM! Now!" 

findURL(x)

[1] http://bit.ly/SS/VUEr).http://bit.ly/14pwinr)? http://bit.ly/108vJOM!

和

findURL2 <- function(x){
  m <- gregexpr("www[^[:space:]]+", x, perl=TRUE)
  w <- unlist(regmatches(x,m))
  op <- paste(w,collapse=" ")
  return(op)
}


y <-  "This is an www.example.com/store/locator. of the type of www.example.com/Google/Voice. data I'd like to extract www.example.com/network. get it?"  

findURL2(y)     

[1] www.example.com/store/locator. www.example.com/Google/Voice. www.example.com/network.

有没有办法修改这些功能，以便. ) ? !或, OR（如果可能）找到). )? )!或),在字符串的末尾后跟一个空格（即标点符号：句点，括号，问号，感叹号或逗号在URL字符串末尾后跟空格）以便不提取它们？

Answer 1

使用积极的前瞻，你也可以将两者结合起来......

findURL <- function(x){
  m <- gregexpr("\\b(?:www|http)[^[:space:]]+?(?=[^\\s\\w]*(?:\\s|$))", x, perl=TRUE)
  w <- unlist(regmatches(x,m))
  op <- paste(w,collapse=" ")
  return(op)
}

x <- "find out more at http://bit.ly/SS/VUEr). check it out here http://bit.ly/14pwinr)? http://bit.ly/108vJOM! Now!" 
y <-  "This is an www.example.com/store/locator. of the type of www.example.com/Google/Voice. data I'd like to extract www.example.com/network. get it?"

findURL(x)
findURL(y)

# [1] "http://bit.ly/SS/VUEr http://bit.ly/14pwinr http://bit.ly/108vJOM"

# [1] "www.example.com/store/locator www.example.com/Google/Voice www.example.com/network"

在R Regex中，忽略URL字符串末尾的一些标点符号

1 个答案: