CODEWITHSUNDEEP
regexr
Rahul Agarwal
Rahul Agarwal

Reputation: 4100

Extract words containing special character in R

I want to extract words which have "@" symbol in it and remove all the other words. So, my data will look like this: 

Author Content 
Name1  Hi,@tim how are you @Blue. 
Name2  @xyz, are you ok? 
Name3  it is good @my @you

where author and content are column names.

I want data in below format:

Author Content
Name1  tim
Name1  Blue
Name2  xyz
Name3  my
Name3  you

So, I only want words which have "@" symbol with it and drop everything else.

Upvotes: 0

Views: 1007

Answers (1)

akrun
akrun

Reputation: 887038

We can use str_extract_all from stringr to extract the words (\\w+) that follow @ in the 'Content' column grouped by 'Author'. Here, I used data.table methods to call the group by operation (after converting the 'data.frame' to 'data.table' (setDT(df1)). 

library(data.table)
library(stringr)
setDT(df1)[, .(Content=unlist(str_extract_all(Content, 
                                     "(?<=@)\\w+"))), by = Author]
#    Author Content
#1:  Name1     tim
#2:  Name1    Blue
#3:  Name2     xyz
#4:  Name3      my
#5:  Name3     you

data

df1 <- structure(list(Author = c("Name1", "Name2", 
"Name3"), Content = c("Hi,@tim how are you @Blue.", 
"@xyz, are you ok?", "it is good @my @you")), 
.Names = c("Author", "Content"), class = "data.frame", 
 row.names = c(NA, -3L))

Upvotes: 3

Related Questions