R语言中句子中的精确匹配词和词典中的精确匹配词

我有以下数据框，其中包含代表字典的句子和词性/否定词：

sent <- data.frame(words = c("just right size and i love this notebook", "benefits great laptop",
                         "wouldnt bad notebook", "very good quality", "orgtop",
                         "great improvement for that bad product but overall is not good", "notebook is not good but i love batterytop"), user = c(1,2,3,4,5,6,7),
               stringsAsFactors=F)

posWords <- c("great","improvement","love","great improvement","very good","good","right","very","benefits",
          "extra","benefit","top","extraordinarily","extraordinary","super","benefits super","good","benefits great")
negWords <- c("hate","bad","not good","horrible")

在每一个句子中都有独特的词语。这是一个问题，当我不能做精确匹配

---

拜托，谁能帮我一下吗。我真的不知道该怎么做。我将感谢你的任何帮助或建议。提前非常感谢。

已经为R实现了许多极性算法，包括Matthew Jockeys新的GitHub包。你看过现有的实现吗？是的，我看过github，浏览了很多网页，没有发现任何类似的东西：-(

counter <- 0
dataOut <- ldply(strsplit(as.character(sent$words), " "), 
             function(x) {
               counter <<- counter + 1
               p = which(x %in% posWords)
               n = which(x %in% negWords)
               positive <- vapply(p, function(i) paste0(c(x[i - 2], x[i - 1], x[i], x[i + 1], x[i + 2]), collapse = " "), character(1))
               negative <- vapply(n, function(i) paste0(c(x[i - 2], x[i - 1], x[i], x[i + 1], x[i + 2]), collapse = " "), character(1))
               if(length(positive) > 0 | length(negative) > 0) {
                 cbind(user = counter, word = c(positive, negative), val = rep(c(1, -1), c(length(p), length(n))))
               }
             })

strsplit(as.character(sent$words), " ")