gsubfn类似于gsub，但不是用替换字符串替换匹配项，而是允许用户指定一个函数(可能在公式符号).然后，它将匹配项传递给正则表达式中的捕获组，即，将匹配项传递给正则表达式中带括号的部分，作为单独的参数，并将整个匹配项替换为函数的输出.因此，我们匹配"(\\d+)(-| to | bis | jusqu'à )(\\d+)"，这将导致三个捕获组，因此该函数需要3个参数.在函数中，我们将seq与其中的第一个和第三个一起使用.请注意，seq可以接受字符参数并将其解释为数字，因此我们不必将参数转换为数字.

gsubfn in the gsubfn package is like gsub but instead of replacing the match with a replacement string it allows the user to specify a function (possibly in formula notation as done here). It then passes the matches to the capture groups in the regular expression, i.e. the matches to the parenthesized parts of the regular expression, as separate arguments and replaces the entire match with the output of the function. Thus we match "(\\d+)(-| to | bis | jusqu'à )(\\d+)" which results in three capture groups so 3 arguments to the function. In the function we use seq with the first and third of these. Note that seq can take character arguments and interpret them as numeric so we did not have to convert the arguments to numeric.

因此，我们得到了这种单线:

Thus we get this one-liner:

library(gsubfn)
s <- c(a, b) # test input strings

gsubfn("(\\d+)(-| to | bis | jusqu'à )(\\d+)", ~ paste(seq(..1, ..3), collapse = ","), s)

给予:

[1] "I would like to buy 1,2,3 cats" "I would like to buy 1,2,3 cats"