r - 仅保留在向量 R 中找到的数据框中的单词

Question

我需要从如下所示的数据框中删除所有非英语单词:

ID     text
1      they all went to the store bonkobuns and bought chicken
2      if we believe no exomunch standards are in order then we're ok
3      living among the calipodians seems reasonable  
4      given the state of all relimited editions we should be fine

我想以这样的数据框结束:

 ID     text
 1      they all went to the store and bought chicken
 2      if we believe no standards are in order then we're ok
 3      living among the seems reasonable  
 4      given the state of all editions we should be fine

我有一个包含所有英文单词的向量:word_vec

我可以使用 tm 包从数据框中删除向量中的所有单词

for(k in 1:nrow(frame){
    for(i in 1:length(word_vec)){
        frame[k,] <- removeWords(frame[i,],word_vec[i])
    }
}

但我想做相反的事情。我只想“保留”向量中的单词。

Answer 1

这里有一个简单的方法:

txt <- "Hi this is an example"
words <- c("this", "is", "an", "example")
paste(intersect(strsplit(txt, "\\s")[[1]], words), collapse=" ")
[1] "this is an example"

当然，细节决定成败，因此您可能需要稍微调整一下以考虑撇号和其他标点符号。