r - 如何使用 R 删除字符串中特定单词之前和之后的单词？

Question

我有以下 df:

structure(list(id = c(9L, 10L, 11L, 96L, 97L, 101L, 103L, 248L, 
499L, 1044L), leg_activity = c("home, adpt, shop, car_passenger, home, adpt, work, adpt, home pt,, work pt,, outside, outside, outside pt,, outside pt,, pt, home", 
"home pt,, pt, outside, outside, outside, outside pt,, pt, home, car, leisure, car, other, car, leisure, car, leisure, car, other, car, leisure, car, other, car, leisure, car, home, adpt, leisure, adpt, home", 
"home pt,, work, adpt, home", "home, car, work, car, home pt,, work, adpt, home", 
"home, adpt, work, car_passenger, leisure, car_passenger, work, adpt, home, car_passenger, outside, outside, outside, car_passenger, outside, outside, outside, car_passenger, home", 
"home, bike, outside, outside, outside, car_passenger, outside, outside, outside, car_passenger, outside, outside, outside, bike, home, adpt, leisure, adpt, home, bike, leisure, bike, home", 
"home, adpt, work, adpt, home, walk, other, pt, home", "home, adpt, work, walk, home, adpt, work, walk, home", 
"home, adpt, leisure, adpt, home, bike, outside, outside, outside, bike, home", 
"home, pt, work, adpt, home, adpt, work, adpt, home")), row.names = c(NA, 
10L), class = "data.frame")

如您所见，leg_activity 列包含字符串。我想要的是删除所有与 outside 相关的单词。

更具体一点，让我们以假设的行为例:

"home, bike, outside, outside, outside, car_passenger, outside, outside,  bike, home, adpt, bike, leisure, bike, home"

目标是删除 outside 之前的单词以及 outside 之后的单词，最终，outside 应该被删除也。所需的输出:

"home, home, adpt, bike, leisure, bike, home"

到目前为止我只能删除特定的单词

agents$leg_activity <- gsub(', home', '', agents$leg_activity)

非常感谢您的帮助!

Answer 1

我们可以用逗号分割字符串，使用 grep 获取 "outside" 所在的位置，并删除它之前和之后的值。

agents$new_col <- sapply(strsplit(agents$leg_activity, ',{1,}\\s'), function(x) {
              inds <-  grep('outside', x)
              if(length(inds)) toString(x[-unique(c(inds - 1, inds, inds + 1))])
              else toString(x)
})
agents$new_col

# [1] "home, adpt, shop, car_passenger, home, adpt, work, adpt, home pt, home"                                                                                       
# [2] "home pt, home, car, leisure, car, other, car, leisure, car, leisure, car, other, car, leisure, car, other, car, leisure, car, home, adpt, leisure, adpt, home"
# [3] "home pt, work, adpt, home"                                                                                                                                    
# [4] "home, car, work, car, home pt, work, adpt, home"                                                                                                              
# [5] "home, adpt, work, car_passenger, leisure, car_passenger, work, adpt, home, home"                                                                              
# [6] "home, home, adpt, leisure, adpt, home, bike, leisure, bike, home"                                                                                             
# [7] "home, adpt, work, adpt, home, walk, other, pt, home"                                                                                                          
# [8] "home, adpt, work, walk, home, adpt, work, walk, home"                                                                                                         
# [9] "home, adpt, leisure, adpt, home, home"                                                                                                                        
#[10] "home, pt, work, adpt, home, adpt, work, adpt, home"