CODEWITHSUNDEEP
rdplyrtidyversestringrtidytable
MYaseen208
MYaseen208

Reputation: 23898

tidyverse: filter with str_detect

I want to use filter command from dplyr along with str_detect.

library(tidyverse)

dt1 <- 
  tibble(
      No   = c(1, 2, 3, 4)
    , Text = c("I have a pen.", "I have a book.", "I have a pencile.", "I have a pen and a book.")
    )

dt1
# A tibble: 4 x 2
     No Text                    
  <dbl> <chr>                   
1     1 I have a pen.           
2     2 I have a book.          
3     3 I have a pencile.       
4     4 I have a pen and a book.


MatchText <- c("Pen", "Book")

dt1 %>% 
  filter(str_detect(Text,  regex(paste0(MatchText, collapse = '|'), ignore_case = TRUE)))

# A tibble: 4 x 2
     No Text                    
  <dbl> <chr>                   
1     1 I have a pen.           
2     2 I have a book.          
3     3 I have a pencile.       
4     4 I have a pen and a book.

Required Output

I want the following output in more efficient way (since in my original problem there would be many unknown element of MatchText).

dt1 %>% 
  filter(str_detect(Text,  regex("Pen", ignore_case = TRUE))) %>% 
  select(-Text) %>% 
  mutate(MatchText = "Pen") %>% 
  bind_rows(
    dt1 %>% 
      filter(str_detect(Text,  regex("Book", ignore_case = TRUE))) %>% 
      select(-Text) %>% 
      mutate(MatchText = "Book")
  )

# A tibble: 5 x 2
     No MatchText
  <dbl> <chr>    
1     1 Pen      
2     3 Pen      
3     4 Pen      
4     2 Book     
5     4 Book

Any hint to accomplish the above task more efficiently.

Upvotes: 0

Views: 1759

Answers (2)

Gregor Thomas
Gregor Thomas

Reputation: 145775

library(tidyverse)
dt1 %>%
  mutate(
    result = str_extract_all(Text, regex(paste0("\\b", MatchText, "\\b", collapse = '|'),ignore_case = TRUE))
  ) %>%
  unnest(result) %>%
  select(-Text)
# # A tibble: 4 x 2
#      No result
#   <dbl> <chr> 
# 1     1 pen   
# 2     2 book  
# 3     4 pen   
# 4     4 book

I'm not sure what happened to the "whole words" part of your question after edits - I left in the word boundaries to match whole words, but since "pen" isn't a whole word match for "pencile", my result doesn't match yours. Get rid of the \\b if you want partial word matches.

Upvotes: 2

pieterbons
pieterbons

Reputation: 1724

str_extract_all() gives multiple matches which you can unnest into separate rows to get your desired output. If you want you can still use the paste+collapse method to generate the pattern from a vector.

library(stringr)
dt1 %>% 
  mutate(match = str_extract_all(tolower(Text), "pen|book")) %>% 
  unnest(match) %>% 
  select(-Text)

Upvotes: 1

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