How do I compare a string with a #single word?
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Hello I am trying to compare a string with 'word'. for example if the word ‘retro’ is in the text file, and ‘#retro’ appear in the str,
str = It was #crazy #retro.
word = 'retro'
How do I compare the str with word including the hashtag. I tried using
strfind(lower(str), '#line2')
but it gave me an empty vector.
Thank you.
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Accepted Answer
Guillaume
on 27 Feb 2015
Edited: Guillaume
on 28 Feb 2015
All of the solution proposed so far have the problem that they'll find the hashtag #retro in the hashtag #retrorocket, which I don't think is wanted.
At the end of the day, a very good parser for strings has been invented long ago, it's called a regular expression. Here is a way to get your matches without the need of a loop:
hiplist = {'denim'; 'vinyl'; 'retro'};
teststr = 'the denim #vinyl was #crazy #retro but the #retrorocket went backward';
%build regular expression from hitlist:
regpattern = sprintf('\\<(?<=#)(%s)\\>', strjoin(hiplist, '|'));
matches = regexp(teststr, regpattern, 'match')
The pattern I've built only match hashtags surrounded by whitespaces (regular spaces, newlines, tabs, etc.) or at the beginning and end of the string. A hashtag followed by a punctuation mark will not be detected, but it's a fairly small change to the regex if wanted.
8 Comments
Guillaume
on 28 Feb 2015
I've given you 99% of the solution in my last answer. You only need to modify slightly one of the regular expression (and it's just removing part of it) and make it case insensitive (it's explained how in the doc), add one line to calculate the score and you're done.
As it is an assignment, I'm not going to help you any further.
More Answers (2)
Image Analyst
on 27 Feb 2015
Not sure what you're exactly looking to do so I just offer some possibilities:
str = 'It was #crazy #retro.'
word = 'retro'
hashLocations = str == '#' % Logical vector
hashIndexes = find(hashLocations) % Actual index numbers.
location = strfind(lower(str), '#retro') + 1 % Skips past #
location = strfind(lower(str), word)
In command window:
hashLocations =
0 0 0 0 0 0 0 1 0 0 0 0 0 0 1 0 0 0 0 0 0
hashIndexes =
8 15
location =
16
location =
16
Joseph Cheng
on 27 Feb 2015
Edited: Joseph Cheng
on 27 Feb 2015
you can try something like this where hiplist is your hipster word dictionary. Then in my loop there you test for hits against the dictionary in the test string and then look for n-1 index for whether it was a pound sign and award points for each one.
hiplist = [{'denim'};{'vinyl'};{'retro'}];
teststr = 'the denim #vinyl was #crazy #retro.';
pointsawarded=0;
for ind = 1:length(hiplist)
det = strfind(teststr,hiplist{ind});
if ~isempty(det)
if det>1 & teststr(det-1)=='#'
pointsawarded = pointsawarded+2;
end
end
end
disp(teststr)
disp(['got ' num2str(pointsawarded) ' points'])
oh and use lower such that the detection isn't case sensitive.
5 Comments
Joseph Cheng
on 27 Feb 2015
Edited: Joseph Cheng
on 27 Feb 2015
good call, i don't deal with cells often when hard coded in.
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