[LON-CAPA-users] Regular expressions in string response

[Gerd Kortemeyer]

Hi,

On May 1, 2007, at 8:33 AM, Robert_Brewington@er.monroe.edu wrote:

>
> I am trying to set up a string response question that takes the  
> student
> answer and removes blanks before comparing to the correct answer.  
> Hopefully
> someone has a code snippet that does this?
>
> Student input:
> a b  c
>
> I want to match to
> /^(abc|acb|bca)\b)

\s* matches any number of spaces, including zero:

/^(a\s*b\s*c|a\s*c\s* ...) ...

>
> (Incidentally, what does the "b" do in this expression?)

Matches a word boundary, and is not appropriate if you want to  
consider spaces. Your whole expression would be

/^\s*(a\s*b\s*c|a\s*c\s*b|b\s*c\s*a)\s*$/

>
> I am looking for something like the vi command to remove spaces:
> s/ //g

Rather than removing them, I would match them.

See

   http://www.regular-expressions.info/

As the saying goes:

     You have a problem, and think: "Oh, I'll just use a regular  
expression!" - now you have two problems.

But seriously, I love regular expressions.

- Gerd.