Question

Consider the following strings:

1) Scheme ID: abc-456-hu5t10 (High priority) *****

2) Scheme ID: frt-78f-hj542w (Balanced)

3) Scheme ID: 23f-f974-nm54w (super formula run) *****

and so on in the above format – the parts in bold are changes across the strings.

==> Imagine I’ve many strings of format Shown above.
I want to pick 3 substrings (As shown in BOLD below) from the each of the above strings.

• 1st substring containing the alphanumeric value (in eg above it’s “abc-456-hu5t10”)
• 2nd substring containing the word (in eg above it’s “High priority”)
• 3rd substring containing * (IF * is present at the end of the string ELSE leave it )

How do I pick these 3 substrings from each string shown above? I know it can be done using regular expressions in Perl… Can you help with this?

Answer 1

You could do something like this:

my $data = <<END;
1) Scheme ID: abc-456-hu5t10 (High priority) *
2) Scheme ID: frt-78f-hj542w (Balanced)
3) Scheme ID: 23f-f974-nm54w (super formula run) *
END

foreach (split(/\n/,$data)) {
  $_ =~ /Scheme ID: ([a-z0-9-]+)\s+\(([^)]+)\)\s*(\*)?/ || next;
  my ($id,$word,$star) = ($1,$2,$3);
  print "$id $word $star\n";
}

The key thing is the Regular expression:

Scheme ID: ([a-z0-9-]+)\s+\(([^)]+)\)\s*(\*)?

Which breaks up as follows.

The fixed String “Scheme ID: “:

Scheme ID: 

Followed by one or more of the characters a-z, 0-9 or -. We use the brackets to capture it as $1:

([a-z0-9-]+)

Followed by one or more whitespace characters:

\s+

Followed by an opening bracket (which we escape) followed by any number of characters which aren’t a close bracket, and then a closing bracket (escaped). We use unescaped brackets to capture the words as $2:

\(([^)]+)\)

Followed by some spaces any maybe a *, captured as $3:

\s*(\*)?