CODEWITHSUNDEEP
rstringr
MetaPhilosopher
MetaPhilosopher

Reputation: 131

How to retain a specific word in a string throughout the column and remove all the rest?

My dataframe is this:

data <- data.frame(column = c("word1 word2 word3", "word2 word1", "word3 word2", "word1 word2", "word3", "word1 word2"))
data

  column
1 word1 word2 word3
2 word2 word1
3 word3 word2
4 word1 word2
5 word3
6 word1 word2

I want to retain the part "word1" in all rows where it occurs and remove the other parts of those strings.

My preferred output is this:

  column
1 word1
2 word1
3 word3 word2
4 word1
5 word3
6 word1

I tried data$column %>% str_replace("^[word1]*", " "), but that didn't do what I wanted.

Upvotes: 0

Views: 172

Answers (2)

AndS.
AndS.

Reputation: 8110

Another option that checks if word1 is in the column and then replaces the rest if it is.

library(tidyverse)

data <- data_frame(column = c("word1 word2 word3", "word2 word1", "word3 word2", "word1 word2", "word3", "word1 word2"))

data %>% mutate(column = if_else(grepl("word1", column), "word1", column))
#> # A tibble: 6 x 1
#>   column     
#>   <chr>      
#> 1 word1      
#> 2 word1      
#> 3 word3 word2
#> 4 word1      
#> 5 word3      
#> 6 word1

Created on 2018-08-25 by the reprex package (v0.2.0).

Upvotes: 0

Maurits Evers
Maurits Evers

Reputation: 50678

Here is a possibility

library(tidyverse)
data %>% mutate(column = str_replace(column, "^.*word1.*$", "word1"))
       column
1       word1
2       word1
3 word3 word2
4       word1
5       word3
6       word1

or with a capture group

data %>% mutate(column = str_replace(column, "^.*(word1).*$", "\\1"))

Upvotes: 1

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