regex match on nothing

[John]

Hi

my $x='Fred's book';
or $x="Fred's book";
or $x-'Freds book';

if ($x =~ s /Fred('|\')s book/xxxxx/);

How can I modify this when there is nothing between Fred and s?

Regards
John

 

[Josef Moellers]

Hi

my $x='Fred's book';
or $x="Fred's book";
or $x-'Freds book';

if ($x =~ s /Fred('|\')s book/xxxxx/);

How can I modify this when there is nothing between Fred and s?

Just put a question mark after the closing parenthesis:

if ($x =~ s/Fred('|\')?s book/xxxxx/) {

 

[John W. Krahn]

Hi

my $x='Fred's book';
or $x="Fred's book";
or $x-'Freds book';

if ($x =~ s /Fred('|\')s book/xxxxx/);

How can I modify this when there is nothing between Fred and s?

Add a third alternative, zero-width match:

if ( $x =~ s/Fred(?:'|'|)s book/xxxxx/ )



John

 

[John]

Hi

my $x='Fred's book';
or $x="Fred's book";
or $x-'Freds book';

if ($x =~ s /Fred('|\')s book/xxxxx/);

How can I modify this when there is nothing between Fred and s?

Regards
John

Many thanks. John.