r - 如何取一个词并根据该词在评论中的出现创建一个指示变量？

Question

我有一个单词向量和一个评论向量:

word.list <- c("very", "experience", "glad")

comments  <- c("very good experience. first time I have been and I would definitely come back.",
               "glad I scheduled an appointment.",
               "the staff have become more cordial.",
               "the experience i had was not good at all.",
               "i am very glad")

我想创建一个看起来像

的数据框

df <- data.frame(comments = c("very good experience. first time I have been and I would definitely come back.",
               "glad I scheduled an appointment.",
               "the staff have become more cordial.",
               "the experience i had was not good at all.",
               "i am very glad"),
               very = c(1,0,0,0,1),
               glad = c(0,1,0,0,1),
               experience = c(1,0,0,1,0))

我有 12,000 多条评论和 20 个单词，我想用它来做这件事。我该如何有效地做到这一点？对于循环？还有其他方法吗？

Answer 1

一种方式是stringi和gdapTools包的组合，即

library(stringi)
library(qdapTools)

mtabulate(stri_extract_all(comments, regex = paste(word.list, collapse = '|')))
#  experience glad very
#1          1    0    1
#2          0    1    0
#3          0    0    0
#4          1    0    0
#5          0    1    1

然后可以使用cbind或者data.frame来绑定(bind)，

cbind(comments, mtabulate(stri_extract_all(comments, regex = paste(word.list, collapse = '|')))))