On Tue, 19 Apr 2005 13:19:31 -0400, Jay Savage wrote
> On 4/19/05, Keith Worthington <[EMAIL PROTECTED]> wrote:
> > On Tue, 19 Apr 2005 10:23:00 -0400, Jay Savage wrote
> > > On 4/19/05, Keith Worthington <[EMAIL PROTECTED]> wrote:
> > > > Hi All,
> > > >
> > > > Many thanks to Jay for his examples I have now written a perl script
> > > > that is munging a text file. Eventually I will move the perl code
> > > > into a function inside a postgresql database.
> > > >
> > > > I am processing inputs like the following:
> > > >
> > > > 815 HTPP Black 2in sq Border: RMFP025BK Size: 7'10" x 16'
> > > > Tag: None
> > > > 3000 HTPP Black 4in sq Border: WNY200BK Size: 17' x 50'
> > > > Tag: None
> > > > 3000 HTPP Black 4in sq Border: WNY200BK Size: 12' x 12'2"
> > > > Tag: None
> > > > Netform Lily Pad Net Size: 5' X 32' W & L Body Length:24'
> > > > 250 HTPP Black 1in sq Border: TW84NTBK Size: 9' x 25'
> > > > Tag: 200' sec
> > > > 1250 HTPP Yellow 2in sq Border: None Size: 6'1" x 12'7"
> > > > Tag: 1855mm x 3840mm
> > > > Here is the code that I have written so far.
> > > >
> > > > #!/usr/bin/env perl
> > > > use strict;
> > > > use warnings;
> > > >
> > > > open(INFILE, "input.txt") or die "Can't open input.txt: $!";
> > > >
> > > > while (<INFILE>) { # assigns each line in turn to $_
> > > > my $v_border_id = "";
> > > > my $v_size = "";
> > > > my $v_length = "";
> > > > my $v_width = "";
> > > > my $v_tag = "";
> > > >
> > > > # Echo out the input line.
> > > > print "\nInput line:\n $_";
> > > > # Perform a case insensitive check for the proper data format.
> > > > #if (/(?i)border:.*size.*tag:.*/){
> > > > # Perform a case insensitive check for the proper data format.
> > > > # Capture the desired parts of the data using parentheses.
> > > > if (/(?i).*border:[ ]*(.*)[ ]*size:[ ]*(.*)[ ]*tag:[ ]*(.*)[
]*/){
> > > > print "properly formatted\n";
> > > > # Check for no border.
> > > > if ($1 =~ /(?i)none/){
> > > > $v_border_id = "";
> > > > } else {
> > > > $v_border_id = $1;
> > > > }
> > > > # Parse up the size string.
> > > > my ($v_length, $v_width) = split(/x/, $2);
> > > > print split(/(?i)[ ]*x[ ]*/, $2);
> > > > print "\n";
> > > > # Check for no tag.
> > > > #if ($v_tag =~ /(?i)tag:[ ]*none/){
> > > > if ($3 =~ /(?i)none/){
> > > > $v_tag = "";
> > > > } else {
> > > > $v_tag = $3;
> > > > #$v_tag =~ s/.*(?i)tag:[ ]*//;
> > > > }
> > > > } else {
> > > > print "bad format\n";
> > > > $v_border_id = "";
> > > > $v_size = "";
> > > > $v_tag = "";
> > > > }
> > > > print "Border ID: $v_border_id\n";
> > > > print "Size string: $2\n";
> > > > print "Length string: $v_length\n";
> > > > print "Width string: $v_width\n";
> > > > print "Tag string: $v_tag\n\n";
> > > > }
> > > >
> > > > close INFILE;
> > > >
> > > > Most of the code seems to be working as expected. I seem to be
> > > > having a problem with the split command/assignment as the length
> > > > and width strings are blank. The command is based on Jay's
> > > > example shown here.
> > > >
> > > > > my ($length, $width) = split / x /, $size ;
> > > >
> > > > What I really wanted to do was this.
> > > > my ($v_length, $v_width) = split(/(?i)[ ]*x[ ]*/, $2);
> > > >
> > > > So I put the following in the code to try and understand what
> > > > was going wrong.
> > > > print split(/(?i)[ ]*x[ ]*/, $2);
> > > > print "\n";
> > >
> > > [snip]
> > >
> > > Well, it looks like the immediate issue here is that there is no $2.
> > > The match variables, including $1, $2, etc. are reset /every/ time
> > > you run a regex, whether you use them or not..
> > >
> > > 'if ($1 =~ /(?i)none/){'
> > >
> > > undef'd $1, $2, and $3 so it could reuse them, and then didn't reload
> > > them. The match variables are /very/ temporary; if you're not going
> > > to use them immediately, assign them to a temporary variable.
> > >
> > > Also don't complicate your code unecessarily: if you're never going
> > > to turn off case sensitivity (i.e. with (-?i)), just use /none/i instead
> > > of /(?i)none/. Your eyes will thank you in the long run.
> > >
> > > HTH,
> > >
> > > --jay
> >
> > Okay that makes sense. But if that is what is happening then
> > how come the print statement operating on $2 works just fine?
> >
> > I appreciate the comment on the i modifier. I didn't realize
> > that case sensitivity could be turned off and back on within
> > an expression. Not knowing what the bloody users are going
> > to do I like to have it off all the time.
> >
> > Kind Regards,
> > Keith
> >
>
> Sorry, not enough coffee. $1, $2, etc. actually stay set until
> they're unset, and the scoping is working in your favor here,
> although you'll notice all of the use of uninitialized value errors
> on your last set of splits. Using them at any distance from the
> regex that produced them, though i still likely to produce
> unexpected results. Also, your variables aren't scoped proberly
> either. You're declaring them with my inside an if block, and then
> trying to print them outside.
>
> my ($v_length, $v_width) = split(/(?i)[ ]*x[ ]*/, $2);
>
> defeats the purpose of predeclaring the variable. The second my
> rescopes both variables to the enclosing block. The effect here is
> roughly the same as 'local'.
>
> There may be more going on here, as well.
>
> HTH,
>
> --jay
Thanks. Now I understand the scope issue. I dropped the 'my' out of that
section of the code and things started to work.
No I am off to write my first perl subroutine. Woohoo!
Kind Regards,
Keith
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