如何使用 str_detect 边界（tidyr 包）

Question

这是一些数据。

library(stringr)
library(dplyr)

df <- tibble(sentences)

我想识别所有带有“她”这个词的句子。但这当然也会返回带有“那里”和“这里”之类的词的句子。

df %>% filter(str_detect(sentences, "her"))
# A tibble: 43 x 1
   sentences                                    
   <chr>                                        
 1 The boy was there when the sun rose.         
 2 Help the woman get back to her feet.         
 3 What joy there is in living.                 
 4 There are more than two factors here.        
 5 Cats and dogs each hate the other.           
 6 The wharf could be seen at the farther shore.
 7 The tiny girl took off her hat.              
 8 Write a fond note to the friend you cherish. 
 9 There was a sound of dry leaves outside.     
10 Add the column and put the sum here. 

stringr::str_detect 的文档说：“将字符、单词、行和句子边界与 boundary() 匹配。”我无法弄清楚如何做到这一点，也无法在任何地方找到示例。所有文档示例都涉及str_split 或str_count 函数。

我的问题与this question有关，但我特别想了解如何使用stringr::boundary函数。

Answer 1

我们可以在开头和结尾指定单词边界（\\b）以避免任何部分匹配

library(stringr)
library(dplyr)
df %>% 
    filter(str_detect(sentences, "\\bher\\b"))
#                             sentences
#1 Help the woman get back to her feet.
#2      The tiny girl took off her hat.

或者使用boundary来换行

df %>%
      filter(str_detect(sentences, boundary("her")))