MATLAB Answers

Why do strfind and regexp may lead to a different result?

10 views (last 30 days)
pietro on 12 Jun 2017
Commented: pietro on 13 Jun 2017
Hi all,
I noticed that regexp and strfind may lead to different results. Here an example:
regexp('Infinitely Variable Transmission (IVT)','Infinitely Variable Transmission (IVT)')
Why does it occur?


Adam on 12 Jun 2017
What is that an example of?
>> regexp('Infinitely Variable Transmission','Infinitely Variable Transmission')
ans =
>> strfind('Infinitely Variable Transmission','Infinitely Variable Transmission')
ans =
Stephen Cobeldick
Stephen Cobeldick on 12 Jun 2017
@pietro: if you are planning on using regular expressions then you really need to understand the different meta-characters, such as parentheses. A good place to learn about regular expressions in MATLAB is to read the MATLAB documentation:

Sign in to comment.

Accepted Answer

Adam on 12 Jun 2017
Edited: Adam on 12 Jun 2017
regexp( 'Infinitely Variable Transmission (IVT)', 'Infinitely Variable Transmission \(IVT\)' )
works, but you have to escape the parenthesis as they have special meaning in a regexp expression.
if you look in
doc regexp
in the section headed 'Split Text at Delimiter Using split Keyword', there is an example of this for escaping the ^ symbol.

More Answers (1)

Walter Roberson
Walter Roberson on 12 Jun 2017
In the general case, regexp can return different results if the pattern includes metacharacters.
There is a routine that can be used to "escape" characters so that they are treated literally, but the routine name is not coming to mind at the moment.