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
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