Question

I was wondering if anyone has a quick solution to extracting hashtags from the tweets in R.
For example, given the following string, how can I parse it to extract the word with the hashtag?

string <- 'Crowdsourcing is awesome. #stackoverflow'

Answer 1

Unlike HTML, I expect you probably can parse hashtags with regex.

library(stringr)
string <- "#hashtag Crowd#sourcing is awesome. #stackoverflow #question"
# I don't use Twitter, so maybe this regex is not right 
# for the set of allowable hashtag characters.
hashtag.regex <- perl("(?<=^|\\s)#\\S+")
hashtags <- str_extract_all(string, hashtag.regex)

Which yields:

> print(hashtags)
[[1]]
[1] "#hashtag"       "#stackoverflow" "#question"     

Note that this also works unmodified if string is actually a vector of many tweets. It returns a list of character vectors.