How can I remove duplicate characters from the strings of a column using R? For example, This is my column:
df<- data.frame(name = c(A="a,a,b,c,d,d,d",
B="a,b,b,b,f",
C="d,d,d,d",
D="a,a"))
And my expected column:
df<- data.frame(name = c(A="a,b,c,d",
B="a,b,f",
C="d",
D="a"))
An option with map and strsplit
library(tidyverse)
df %>%
mutate(name = strsplit(as.character(name), ",") %>%
map(~toString(unique(.x))))
# name
#1 a, b, c, d
#2 a, b, f
#3 d
#4 a
Or in base R with regex
sub(",$", "", gsub("([a-z],)\\1+", "\\1", paste0(df$name, ",")))
#[1] "a,b,c,d" "a,b,f" "d" "a"
Using tidyverse we can first add rownames as column, separate comma separated string into separate_rows, group_by rowname and remove duplicated values and convert them to comma separated string again using toString.
library(tidyverse)
df %>%
rownames_to_column() %>%
separate_rows(name, sep = ",") %>%
group_by(rowname) %>%
filter(!duplicated(name)) %>%
summarise(name = toString(name)) %>%
column_to_rownames()
# name
#A a, b, c, d
#B a, b, f
#C d
#D a
Base R approach using sapply which is quite same as @tmfmnk
sapply(strsplit(as.character(df$name), ","), function(x) toString(unique(x)))
#[1] "a, b, c, d" "a, b, f" "d" "a"
One dplyr possibility could be:
df %>%
rowwise() %>%
mutate(name = toString(unique(unlist(strsplit(name, ",")))))
name
<chr>
1 a, b, c, d
2 a, b, f
3 d
4 a
The same with base R:
sapply(df$name, function(x) toString(unique(unlist(strsplit(x, ",")))), USE.NAMES = FALSE)
