MATLAB and Simulink resources for Arduino, LEGO, and Raspberry Pi

Learn moreOpportunities for recent engineering grads.

Apply Today**New to MATLAB?**

Asked by Abim
on 14 Dec 2012

I am writing a script that analyzes the hashtags from tweets that I saved in a text file. So far I managed to count the amount of hashtags in the file:

fid = fopen('Tweets.txt'); numberOfTweets = 0; while i ~= -1 i = fgetl(fid); numberOfTweets = numberOfTweets + 1; end numberOfTweets = numberOfTweets - 1; frewind(fid) for i = 1:numberOfTweets twitterStuff{i} = fgetl(fid); end numberOfHash = 0; for i = 1:numberOfTweets if(strfind(twitterStuff{i}, '#') ~=0); c = strfind(twitterStuff{i}, '#'); [rowHash columnHash] = size(c); numberOfHash = numberOfHash + columnHash; end end

Now, I want to find out what the specific hashtags are and save them into a cell array, but I don't really know how to do that.

*No products are associated with this question.*

Answer by Jonathan Epperl
on 14 Dec 2012

Edited by Jonathan Epperl
on 14 Dec 2012

Accepted answer

You should use regular expressions for that, you can do pretty much anything with them. This should do what you want to, and if not, then it should point you in the right direction:

s = '#Matlab#2012b rocks my #sox # off!' % Match a '#' with zero or more characters that aren't whitespace or '#' after it T = regexp(s,'(#[^ #]*)','tokens') T{:} % Match a '#' with 1 or more characters that aren't whitespace or '#' after it T = regexp(s,'(#[^ #]+)','tokens') T{:} % Match a '#' with 1 or more characters that aren't whitespace or '#' after % it, but don't capture the '#' T = regexp(s,'#([^ #]+)','tokens') T{:}

Answer by Sean de Wolski
on 14 Dec 2012

Edited by Sean de Wolski
on 14 Dec 2012

Using regular expressions:

str = '#MATLAB is an awesome product by #MathWorks';

[matchstart,matchend,~,hashtag] = regexp(str,'(\#(\w*))')

## 2 Comments

## Walter Roberson

Direct link to this comment:http://www.mathworks.com/matlabcentral/answers/56560#comment_117154

Is # by itself a hashtag? Is #this#that with no spaces two hashtags? Is #35 a valid hashtag? Is #? a valid hashtag?

## Abim

Direct link to this comment:http://www.mathworks.com/matlabcentral/answers/56560#comment_117265

When I said counting the amount of hashtags, I just counted the amount of # .But when I say, save the hashtags, I want to save the words contained within the hashtags. technically, #this#that would be two hashtags, but for now I would just want to focus on the basic #this hashtag.