基于多个模式保持分隔符的拆分句子

Question

我有一些句子的分隔模式是“(has|is|thinks)”

我想在第二句中包含分隔符并删除所有尾随空格，如下所示：

mystr1 <- "the bird is now a dog"
mystr2 <- "the small cow thinks like a dog"
mystr3 <- "the fish has become a dog"

结果：

"the bird"          "is now a dog"
"the small cow"     "thinks like a dog"
"the fish"          "has become a dog"

注意： str_split(mystr3, "(has|is|thinks)", n = 2)

导致 "the f" "h has become a dog"

因为“is”是一个分隔符并且是“fish”的一部分

如何最好地做到这一点？

Answer 1

您可以使用正向前瞻模式来保留分隔符和单词边界，以避免在单词中间分裂。

split_sent <- function(x) {
    trimws(stringr::str_split(x, '(?=\\b(has|is|thinks)\\b)', n = 2)[[1]])
}

split_sent(mystr1)
#[1] "the bird"     "is now a dog"
split_sent(mystr2)
#[1] "the small cow"     "thinks like a dog"
split_sent(mystr3)
#[1] "the fish"         "has become a dog"