be very careful with exists, it auto creates the structure
i.e.
use Data::Dumper;
my %hash;
if (exists $hash{a}{b}) {
}
print Dumper(\%hash)
then the next time you use exists it is there.
defined is much safer as it doesnt do this.
-----Original Message-----
From: Beginner [mailto:[EMAIL PROTECTED]
Sent: 29 October 2007 15:30
To: beginners @ perl. org
Subject: Re: array within array
On 29 Oct 2007 at 8:42, Mike Tran wrote:
> Hey all,
>
>
>
> I'm new with Perl and need help with this simple script. I'm still
> playing around with the script below to get a feel for Perl. My script
> below is incomplete and I'm doing an array within an array which is
> incorrect. Please help.
>
>
>
> Here's what I want to do; I have to flat files (pipe delimited, export
> from a database) that I want to parse through and assign variables for
> each column. Basically, I want to parse through exclude_bases.txt and
> do: if base_no in exclude_bases.txt equals to base_no in base.txt then
> search in the "description" field of base.txt for the string listed in
> the "keyword" field in exclude_bases.tx and replace with "new_keyword"
> in exclude_bases.txt and write the out put into a new file called
> "new_bases.txt".
>
>
>
> Any suggestions on how I could accomplish the above task is greatly
> appreciated. Thanks all.
>
>
>
> Flat Files:
>
>
>
> base.txt:
>
> base_no|name|description
>
> 10000|test|test desc
>
> 10001|test2|test desc 2
>
> 10002|test3|test desc 3
>
>
>
> exclude_bases.txt:
>
> base_no|keyword|new_keyword|
>
> 10000|test desc|testdesc|0
>
> 10001|test desc 2|testdesc2|0
>
> 10002|test desc 3|testdesc3|1
>
>
>
>
>
>
>
> #!/usr/bin/perl
>
>
>
> use strict;
>
> use warnings;
>
>
>
> my $exclude_bases = "exclude_bases.txt";
>
> my $current_base = "base.txt";
>
> my $output = "new_bases.txt";
>
>
>
> my %exclude_bases;
>
> my $exclude_text;
>
> my $exbase_no;
>
> my $keyword;
>
> my $new_keyword;
>
>
>
> open(EXCLUDE,"exclude_bases.txt" )|| die("Could not open file!");
>
> %exclude_bases=<EXCLUDE>;
>
> close(EXCLUDE);
>
>
>
> my $base_no ="";
>
> my $name="";
>
> my $description="";
>
> my $current_base="";
>
> my $base_text="";
>
> my %bases;
>
>
>
> open(BASE,"base.txt")|| die("Could not open file!");
>
> %bases=<BASE>;
>
> close(BASE);
>
>
>
> #choping lines and assign variables to base.txt
>
> foreach $base_text (%bases)
>
> {
>
> chop($base_text);
>
> ($base_no,$name,$description)=split(/\|/,$base_text);
>
>
>
> #choping lines and assign variables to exclude_bases.txt
>
> foreach $exclude_text (%exclude_bases)
>
> {
>
> chop($exclude_text);
>
> ($exbase_no,$keyword,$new_keyword)=split(/\|/,$base_text);
>
>
>
> if ($exbase_no=$base_no) {
>
> $keyword =~ s/$keyword/$new_keyword/g;}
>
Well here my effort. It should help you get closer to what your after
but it's not complete. I would use hashes not arrays, you'll find
them extremely useful for de-duping data
I haven't run the script below, please do a perl -c first.
Check out "exists"
perldoc -f exists
#!/usr/bin/perl
use strict; # Well done
use warnings; # ditto.
my $exclude_bases = "exclude_bases.txt";
open(EXCLUDE,"excludes.txt" )|| die("Could not open file!");
while (<EXCLUDE>) {
chomp;
my @fields = split(/|/,$_);
$exclude_bases{$F[0]} = 0; # $f[0] contains base_no
}
close(EXCLUDE);
open(BASE,"base.txt")|| die("Could not open file!");
while (<BASE>) {
chomp;
my @fields = split(/|/,$_);
if (! exists($exlude_bases{$_}) ) {
print "$f[2]\n";
}
}
close(BASE);
HTH,
Dp.
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