Nrthugu

Is there a way in perl to replace all text in input line except ones within single quotes(There could be more than one) using regex, I have achieved this using the code below but would like to see if it can be done with regex and map.

while (<>) {

    my $m=0;

    for (split(//)) { 

        if (/'/ and ! $m) {

            $m=1;

            print;

        }

        elsif (/'/ and $m) {

            $m=0;

            print;

        }

        elsif ($m) {

            print;

        }

        else {

            print lc;

        }

    }

} 

**Sample input:**



and (t.TARGET_TYPE='RAC_DATABASE' or (t.TARGET_TYPE='ORACLE_DATABASE' and t.TYPE_QUALIFIER3 != 'racinst'))



**Sample output:**



and (t.target_type='RAC_DATABASE' or (t.target_type='ORACLE_DATABASE' and t.type_qualifier3 != 'racinst'))

You can give this a shot. All one regexp.

$str =~ s/(?:^|'[^']*')K[^']*/lc($&)/ge;

Or, cleaner and more documented (this is semantically equivalent to the above)

$str =~ s/

  (?:

    ^     | # Match either the start of the string, or

    '[^']*' # some text in quotes.

  )K       # Then ignore that part,

            # because we want to leave it be.

  [^']*     # Take the text after it, and

            # lowercase it.

  /lc($&)/gex;

The g flag tells the regexp to run as many times as necessary. e tells it that the substitution portion (lc($&), in our case) is Perl code, not just text. x lets us put those comments in there so that the regexp isn't total gibberish.

Don't you play too hard with regexp for such a simple job?

Why not get the kid 'split' for it today?

#!/usr/bin/perl

while (<>)

{

    @F = split "'";

    @F = map { $_ % 2 ? $F[$_] : lc $F[$_] } (0..@F);

    print join "'", @F;

}

The above is for understanding. We often join the latter two lines reasonably into:

print join "'", map { $_ % 2 ? $F[$_] : lc $F[$_] } (0..@F);

Or enjoy more, making it a one-liner? (in bash shell) In concept, it looks like:

perl -pF/'/ -e 'join "'", map { $_ % 2 ? $F[$_] : lc $F[$_] } (0..@F);' YOUR_FILE

In reality, however, we need to respect the shell and do some escape (hard) job:

perl -pF/'/ -e 'join "'"'"'", map { $_ % 2 ? $F[$_] : lc $F[$_] } (0..@F);' YOUR_FILE

(The single-quoted single quote needs to become 5 letters: '"'"')

If it doesn't help your job, it helps sleep.

One more variant with Perl one-liner. I'm using hex x27 for single quotes

$ cat sql_str.txt

and (t.TARGET_TYPE='RAC_DATABASE' or (t.TARGET_TYPE='ORACLE_DATABASE' and t.TYPE_QUALIFIER3 != 'racinst'))



$ perl -ne ' { @F=split(/x27/); for my $val (0..$#F) { $F[$val]=lc($F[$val]) if $val%2==0 } ; print join("x27",@F) } ' sql_str.txt

and (t.target_type='RAC_DATABASE' or (t.target_type='ORACLE_DATABASE' and t.type_qualifier3 != 'racinst'))



$