perl string match issues

Question

i have a script in which i need to skip comments, and i am able to achieve it partially...

IN :

{****************************
{test : test...test }

Script:

if ( $data =~  m/(^{\*+$)/ ){
}

With the above match i am able to identify the comment and skip it to get the next line..

Out:
{test : test...test }

If the same comment consists of any space or any character in the place of *, my match fails..

IN:
{** *****    or   {* abccd   or {*abce

All the above cases are failed to skip ... What might be worng in the match,...can any one help me out..

Zaid · Accepted Answer · 2012-10-04 05:51:19Z

1

The $ in your regex is an anchor that denotes the end of the string/line, which insists that the match will happen only when you have a row full of *s after the initial {

Removing this anchor will allow all three cases to match:

for ( '{*********', '{** *****', ,'{* abccd' , '{*abce' ) {

    print "$_ Matches\n" if /^{\*+/;
}

answered Oct 4, 2012 at 5:51

Zaid

37.3k16 gold badges89 silver badges159 bronze badges

Sign up to request clarification or add additional context in comments.

2 Comments

Anil Over a year ago

i tried to remove the anchor but i do get an error...saying.. "Use of uninitialized value in concatenation (.) or string"

Zaid Over a year ago

@NEW : Is the line number corresponding to the regex match, or is it another line?

friedo · Accepted Answer · 2012-10-04 05:52:08Z

0

It's unclear exactly what the syntax for comments is in your text, but given the examples, I'm going to assume that {* at the beginning of a line, followed by anything until the end of the line, is a comment.

In that case, your regex /(^{\*+$)/ won't work. That says:

^ - Match the beginning of the line
{ - Match a {
\*+ - Match one or more *s
$ - Match the end of the line

This pattern won't match if anything else comes between the *s and the end of the line.

Something like /^{\*.+$/ should do what you want. That changes your pattern to match one or more non-newline characters (the .) until you reach the end of the line.

answered Oct 4, 2012 at 5:52

friedo

67.3k17 gold badges119 silver badges186 bronze badges

2 Comments

Anil Over a year ago

i tried using the same but i do get an error...saying.. "Use of uninitialized value in concatenation (.) or string"

friedo Over a year ago

That warning (not error) is unrelated to the particular regex you might be using. Figure out what value is undefined and define it.

Ωmega · Accepted Answer · 2012-10-04 14:52:26Z

0

If you want to allow some other characters behind {* part, then just remove $ from the pattern.

This is a simple Perl code that you can start with:

@data = <main::DATA>;
print map { $_ if !/^{\*+/ } @data;

__DATA__
{****************************
{test : test...test}

Output:

{test : test...test}

Test this code here.

answered Oct 4, 2012 at 14:52

Ωmega

44k35 gold badges143 silver badges213 bronze badges

Collectives™ on Stack Overflow

perl string match issues

3 Answers 3

2 Comments

2 Comments

Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

3 Answers 3

2 Comments

2 Comments

Comments

Your Answer

Sign up or log in

Post as a guest

Related