regexp question

[Bart van den Burg]

Hi

Say i have this code:

perl -we 'my $string = "abc help cba abc help cba"; $string =~
/abc(.*)cba/s; print "$1\n";';

this prints about: " help cba abc help ".
However, i wish for it to only match (the first) " help "...

What do i need to change in order for this to work?

Thanks
Bart

 

[Arndt Jonasson]

Say i have this code:

perl -we 'my $string = "abc help cba abc help cba"; $string =~
/abc(.*)cba/s; print "$1\n";';

this prints about: " help cba abc help ".
However, i wish for it to only match (the first) " help "...

What do i need to change in order for this to work?

Use "*?" for matching:

perl -we 'my $string = "abc help cba abc help cba"; $string =~
/abc(.*?)cba/s; print "$1\n";';

See
perldoc -q greedy.

 

[Bart van den Burg]

Great! Thanks!

 

[D. Marxsen]

perl -we 'my $string = "abc help cba abc help cba"; $string =~
/abc(.*)cba/s; print "$1\n";';

this prints about: " help cba abc help ".
However, i wish for it to only match (the first) " help "...

What do i need to change in order for this to work?

You fell into the "greedy"-trap. Try this:

my $string = "abc help cba abc help cba";
$string =~/abc(.*)cba/s; # Your version
print "$1\n";
$string =~/abc(.*?)cba/s; # Try this
print "$1\n";

Cheers,
Detlef.