r - R：可以从每个句子（行）中提取词组吗？并创建数据框（或矩阵）？

Question

我为每个单词创建了列表以从句子中提取单词，例如像这样

hello<- NULL
for (i in 1:length(text)){
hello[i]<-as.character(regmatches(text[i], gregexpr("[H|h]ello?", text[i])))
}

但是我有超过 25 个单词列表要提取，那是很长的编码。 是否可以从文本数据中提取一组字符（单词）？

下面只是一个伪集合。

words<-c("[H|h]ello","you","so","tea","egg")

text=c("Hello! How's you and how did saturday go?",  
       "hello, I was just texting to see if you'd decided to do anything later",
       "U dun say so early.",
       "WINNER!! As a valued network customer you have been selected" ,
       "Lol you're always so convincing.",
       "Did you catch the bus ? Are you frying an egg ? ",
       "Did you make a tea and egg?"
)

subsets<-NULL
for ( i in 1:length(text)){
.....???
   }

预期输出如下

[1] Hello you
[2] hello you
[3] you
[4] you so
[5] you you egg
[6] you tea egg

标签： rextracttext-mining

Answer 1

在基础 R 中，您可以执行以下操作：

regmatches(text,gregexpr(sprintf("\\b(%s)\\b",paste0(words,collapse = "|")),text))
[[1]]
[1] "Hello" "you"  

[[2]]
[1] "hello" "you"  

[[3]]
[1] "so"

[[4]]
[1] "you"

[[5]]
[1] "you" "so" 

[[6]]
[1] "you" "you" "egg"

[[7]]
[1] "you" "tea" "egg"

取决于你想要的结果：

trimws(gsub(sprintf(".*?\\b(%s).*?|.*$",paste0(words,collapse = "|")),"\\1 ",text))
[1] "Hello you"   "hello you"   "so"          "you"         "you so"      "you you egg"
[7] "you tea egg"