如何用R提取正则匹配结果并合并去重后的匹配项？

要实现提取films前的单词并去重后合并，只需在提取所有匹配项后添加去重步骤即可，具体代码如下：

基础写法 #

text1 <- "Netflix announced 34 new Korean films to hit the streaming platform in 2023, along with 12 Japanese films. The upcoming titles, which Netflix calls their “biggest-ever lineup of Korean films and series."

pattern <- "\\b[[:alpha:]]+\\b(?=\\sfilms)"

# 提取所有匹配的单词
matches <- str_extract_all(text1, pattern)[[1]]
# 去重
unique_matches <- unique(matches)
# 合并为目标格式
paste(unique_matches, collapse = " | ")

管道式写法（tidyverse风格） #

如果你习惯用管道操作，也可以写成更简洁的形式：

library(stringr)
library(purrr)

text1 <- "Netflix announced 34 new Korean films to hit the streaming platform in 2023, along with 12 Japanese films. The upcoming titles, which Netflix calls their “biggest-ever lineup of Korean films and series."

pattern <- "\\b[[:alpha:]]+\\b(?=\\sfilms)"

str_extract_all(text1, pattern) %>%
  pluck(1) %>%  # 从列表中取出匹配的字符向量
  unique() %>%  # 去除重复项
  paste(collapse = " | ")  # 合并为指定格式的字符串

运行以上代码后，输出结果即为：

'Korean | Japanese'

关键步骤说明 #

• str_extract_all(text1, pattern)[[1]]：将提取到的列表型结果转换为字符向量，方便后续处理
• unique()：对字符向量中的元素去重，保留唯一值
• paste(..., collapse = " | ")：将去重后的元素用|连接成单个字符串

内容的提问来源于stack exchange，提问作者Raj