-2

你好，

我想把句子分成两部分，从关键字_1到关键字_2，从关键字_2到句子的结尾，最好使用正则表达式。

例如（我的理想输出 - 如下所示）： 在此处输入图像描述

下面是我制作的一个数据集。

数据集

    library(tibble)

    keyword_1 <- c("coffee", "apple", "rainbow", "strawberry shortcake")
    keyword_2 <- c("life", "new york", "seven colours", "sweet and yummy")

    raw <-
      tibble(
        sentence = c(
          "coffee is keyword_1_1 life is keyword_2_1",
          "apple is keyword_1_2 new york is keyword_2_2",
          "rainbow is keyword_1_3 seven colours is keyword_2_3",
          "strawberry shortcake is keyword_1_4 sweet and yummy is keyword 2_4"
        ))
        
    raw

    #> # A tibble: 4 x 1
    #>   sentence                                                          
    #>   <chr>                                                             
    #> 1 coffee is keyword_1_1 life is keyword_2_1                         
    #> 2 apple is keyword_1_2 new york is keyword_2_2                      
    #> 3 rainbow is keyword_1_3 seven colours is keyword_2_3               
    #> 4 strawberry shortcake is keyword_1_4 sweet and yummy is keyword 2_4

预期输出

library(tibble)

output = tibble(
  output1 = c(
    "coffee is keyword_1_1",
    "apple is keyword_1_2",
    "rainbow is keyword_1_3",
    "strawberry shortcake is keyword_1_4"
  ),
  output2 = c("life is keyword_2_1", "new york is keyword_2_2",
              "seven colours is keyword_2_3", "sweet and yummy is keyword 2_4")
)

output

#> # A tibble: 4 x 2
#>   output1                             output2                       
#>   <chr>                               <chr>                         
#> 1 coffee is keyword_1_1               life is keyword_2_1           
#> 2 apple is keyword_1_2                new york is keyword_2_2       
#> 3 rainbow is keyword_1_3              seven colours is keyword_2_3  
#> 4 strawberry shortcake is keyword_1_4 sweet and yummy is keyword 2_4

由reprex 包（v0.3.0）于 2021-03-18 创建

devtools::session_info()
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#>  collate  en_AU.UTF-8                 
#>  ctype    en_AU.UTF-8                 
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#>  date     2021-03-18                  
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4

2 回答 2

0

这是一种data.table方法，使用后视正则表达式模式进行拆分

library( data.table )
setDT(raw)[, paste0( "output", 1:2 ) := 
             lapply( tstrsplit(sentence, "(?<=_[0-9]{1}_[0-9]{1})", perl = TRUE ), 
                     trimws ) ][, sentence := NULL][]

#                                output1                        output2
# 1:               coffee is keyword_1_1            life is keyword_2_1
# 2:                apple is keyword_1_2        new york is keyword_2_2
# 3:              rainbow is keyword_1_3   seven colours is keyword_2_3
# 4: strawberry shortcake is keyword_1_4 sweet and yummy is keyword 2_4
于 2021-03-18T13:52:11.533 回答
0

假设模式总是“keyword_number_number”，那么第四个入口缺少一个“_”，应该是：

raw[4,1] = "strawberry shortcake is keyword_1_4 sweet and yummy is keyword_2_4"

然后我们可以写：

pattern = "([a-z ]+ keyword_[0-9]_[0-9]) ([a-z ]+ keyword_[0-9]_[0-9])"

a = matrix(NA, nrow(raw), 2)
for(i in 1:nrow(raw)){
  for(j in 1:2)
    a[i,j] = gsub(pattern, paste0("\\",j), raw[i,1])}

输出：

> a
     [,1]                                  [,2]                            
[1,] "coffee is keyword_1_1"               "life is keyword_2_1"           
[2,] "apple is keyword_1_2"                "new york is keyword_2_2"       
[3,] "rainbow is keyword_1_3"              "seven colours is keyword_2_3"  
[4,] "strawberry shortcake is keyword_1_4" "sweet and yummy is keyword_2_4"
于 2021-03-18T13:43:02.647 回答