CODEWITHSUNDEEP
rstringduplicates
TarJae
TarJae

Reputation: 78917

Shortest way to remove duplicate words from string

I have this string:

x <- c("A B B C")

[1] "A B B C"

I am looking for the shortest way to get this:

[1] "A B C"

I have tried this: Removing duplicate words in a string in R

paste(unique(x), collapse = ' ')

[1] "A B B C"
# does not work

Background: In a dataframe column I want to count only the unique word counts.

Upvotes: 2

Views: 572

Answers (4)

GKi
GKi

Reputation: 39657

Just in case the duplicates are not following each other, also using gsub.

x <- c("A B B C")
gsub("\\b(\\S+)\\s+(?=.*\\b\\1\\b)", "", x, perl=TRUE)
#[1] "A B C"

gsub("\\b(\\S+)\\s+(?=.*\\b\\1\\b)", "", "A B B A ABBA", perl=TRUE)
#[1] "B A ABBA"

Upvotes: 3

Mohamed Desouky
Mohamed Desouky

Reputation: 4425

You can use ,

gsub("\\b(\\w+)(?:\\W+\\1\\b)+", "\\1", x)

Upvotes: 2

PaulS
PaulS

Reputation: 25323

Another possible solution, based on stringr::str_split:

library(tidyverse)

str_split(x, " ") %>% unlist %>% unique

#> [1] "A" "B" "C"

Upvotes: 3

akrun
akrun

Reputation: 887038

A regex based approach could be shorter - match the non-white space (\\S+) followed by a white space character (\\s), capture it, followed by one or more occurrence of the backreference, and in the replacement, specify the backreference to return only a single copy of the match

gsub("(\\S+\\s)\\1+", "\\1", x)
[1] "A B C"

Or may need to split the string with strsplit, unlist, get the unique and then paste

paste(unique(unlist(strsplit(x, " "))), collapse = " ")
# [1] "A B C"

Upvotes: 4

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