How do I find the last occurrence of a match using regexp in MATLAB?

If I have the following string in MATLAB:

str = '/* This is a comment */ int x; /* sectionEndExample */';

How do I find the last comment that contains sectionEndExample? I have tried the following:

expr = ['^.*/\*.*sectionEndExample.*\*/'];
sectionEndIdx1 = regexp(str, expr);

But this always returns the sectionEndIdx1 as 1. I am looking in the documentation and have so far played around with the lookAround options. However, I can't figure out a way to do it in MATLAB :(

[Azzi Abdelmalek]

if you knpw the comment sectionEndExample, why are you looking for it?

Or do you want to find the last comment between * ?

[Swati Tiwari]

I apologize for not framing the question correctly. I want to be able to find the last comment in the line. I believe I could get this by tweaking the regular expression. But, my efforts have been in vain.

[Azzi Abdelmalek]

Ok, but what about the answers below?

Answer 1

[Azzi Abdelmalek]

str = '/* This is a comment */ int x; /* sectionEndExample */';
pattern='(/)\*[\w\s]+\*(/)';
[sectionEndIdx1,debut,fin] = regexp(str, pattern,'match','start','end');
sectionEndIdx1=sectionEndIdx1{end}
start_comment=debut(end)
end_comment=fin(end)

Answer 2

[Cedric]

Is it what you want? If so, we can work a bit to improve it (in particular for allowing stars in the comment if relevant, which are not allowed with this pattern).

 >> regexp(str, '[^\*]+(?=\*/$)', 'match')
 ans = 
    ' sectionEndExample '

Answer 3

[Azzi Abdelmalek]

str = '/* This is a comment */ int x; /* sectionEndExample */';
pattern='(?<=/\*)[\w\s]+(?=\*/)';
sectionEndIdx1 = regexp(str, pattern,'match');
sectionEndIdx1=sectionEndIdx1{end}

[Cedric]

This solution is better than mine if there can be code (EDIT: or anything) after the last comment.

[Azzi Abdelmalek]

You are right, even a space will make a problem.

[Swati Tiwari]

Thank you very much for all your help. Really appreciate it. To rephrase the question, I wish to get the start position and the end position of the comment (including the starting '/*' and the ending '*/' that contains the string 'sectionEndExample'.

Answer 4

[Swati Tiwari]

Thank you all. I also figured out a way to do it!

str = '/* This is a sectionEndExample comment */ int x; /* sectionEndExample */';

pattern='/\*[^\*]*sectionEndExample[^\*]*\*/';
sectionEndIdx1 = regexp(str, pattern,'match')

This will find all the comments with the string sectionEndExample.

[Swati Tiwari]

Here, I divided the string into three parts:

1. (anything but a *)* sectionEndExample (anything but a *)*
2. The start comment identifier /*
3. The end comment identifier