Thanks.



I am reading on hashes now and practicing on how to use them. I have not
taken any perl classes..



I just started reading the books.



From: perl-beginner@yahoogroups.com [mailto:perl-beginner@yahoogroups.com]
On Behalf Of Jeff Soules
Sent: Wednesday, June 17, 2009 1:46 PM
To: perl-beginner@yahoogroups.com
Subject: Re: [PBML] Newbie question








You've had prior experience with other programming languages, right?
Using substr() this way is a very C or Java way of doing things.

Read up on hashes ("associative arrays") and the split() function in Perl.

http://www.tutorialspoint.com/perl/perl_hashes.htm is just one of many
possible tutorials about hashes.
http://www.perlmeme.org/howtos/perlfunc/split_function.html seems a
decent enough split() tutorial.
I don't claim anything about the quality of these tutorials (I haven't
actually read them), they just came from the first page of google
results.

The idea of a hash is that it's like an array, but you can access the
individual variables by a text-based key, instead of by a numeric
index. So, instead of having to cycle through your list once for
apples, once for oranges, once for pears, etc., and then re-write your
code when your, err, user decides that the program should also work
for tangerines, instead you can use a hash where the fruit name is the
key and the count is the value. So you could access your hash as
$fruitCount{'Apples'} += 1, say. Or even better,
$fruitCount{$fruitName} += 1;
Doing the latter, you could build the entire hash table without ever
needing to know the types of fruit in advance; and you would
automatically cover every type of fruit mentioned in the input file.
The only question would be, "hey, how do I get the fruit name?"
Well...

With the split() function, you can divide your input lines logically,
instead of by using substr() and hoping that all fruits have the same
number of characters. split() lets you break a string apart according
to a delimiter character. In the case of your example here, you have
the name of a fruit, followed by a pipe |. So that | would be the
delimiting character; what you really want is the fruit name that
comes in front of it. If you split each line along the |, then you
can store the first chunk as the fruit name, and throw away the second
part (since, at least so far, you don't really care what the rest of
the line says).

Once you've built up your hash, you'll want to dump its contents. For
this, you'll need the keys() function, which you'll no doubt find
plenty of information about online.

One of the Perl mottoes is "There's More Than One Way to Do It"
(TMTOWDI) and the solution I'm hinting you at here is just one of many
possible ones (that's what makes Perl fun!) But hopefully this will
set you on the way to finding one of the many solutions.

Do check back!

On Wed, Jun 17, 2009 at 4:17 PM, Kevin Patterson<kpatters@...
<mailto:kpatters%40berkeley.edu> > wrote:
>
>
> Sorry...
>
> Here is what I wrote:
>
> #!/usr/bin/perl
>
> #use warnings;
> #use diagnostics;
>
> my $count = 0;
> my $key_count = 0;
> $Input_File="crapdata1.txt";
> open(INP, $Input_File);
> @by_jobname=<INP>;
> close(INP);
>
> foreach $New_Jobname (@by_jobname)
> {
> $em_job = substr($New_Jobname,11,50);
> $em_key = substr($New_Jobname,11,2);
>
> if ($em_key eq "Apples")
> {
> $count[1] = $count[1] + 1;
> }
>
> }
>
> print "$em_key count is: $count[1]\n";
>
> my $count = 0;
> foreach $New_Jobname (@by_jobname)
> {
> $em_job = substr($New_Jobname,11,50);
> $em_key = substr($New_Jobname,11,2);
>
> if ($em_key eq "Oranges")
> {
> $count[2] = $count[2] + 1;
> }
>
> }
> print "$em_key count is: $count[2]\n";
> exit;
>
> It give me the following results:
>
> Apple Count is: 2
> Oranges Count is: 1
>
> Here is the data.
>
> Apples |Sweet
> Oranges |Seeds
> Apples |Sour
>
> -----Original Message-----
> From: perl-beginner@yahoogroups.com
<mailto:perl-beginner%40yahoogroups.com>
[mailto:perl-beginner@yahoogroups.com
<mailto:perl-beginner%40yahoogroups.com> ]
> On Behalf Of Scot Robnett
> Sent: Wednesday, June 17, 2009 12:22 PM
> To: perl-beginner@yahoogroups.com <mailto:perl-beginner%40yahoogroups.com>

> Subject: RE: [PBML] Newbie question
>
> What is the exact format of the file?
>
> What have you tried so far?
>
> Nobody is going to write the script for you. The group is here to help
> you figure things out when you get stuck or something isn't working, but
> you're supposed to try something first.
>
>
>
> -----Original Message-----
> From: perl-beginner@yahoogroups.com
<mailto:perl-beginner%40yahoogroups.com>
> [mailto:perl-beginner@yahoogroups.com
<mailto:perl-beginner%40yahoogroups.com> ] On Behalf Of Kevin Patterson
> Sent: Wednesday, June 17, 2009 2:11 PM
> To: perl-beginner@yahoogroups.com <mailto:perl-beginner%40yahoogroups.com>

> Subject: [PBML] Newbie question
>
>
> Hello..
>
> I am writing a perl program in windows..
>
> Here is my problem.
>
> I have a file containing data such as:
>
> Apples
>
> Oranges
>
> Pears
>
> Bananas
>
> Plums
>
> Apples
>
> Oranges
>
> Pears
>
> bananas
>
> kiwi
>
> Apples
>
> Oranges
>
> Pears
>
> bananas
>
> I write a program to read this file and create a summary report showing
>
> How many apples:
>
> How many oranges
>
> How many Pears
>
> Can anyone help me??
>
> thanks
>
> [Non-text portions of this message have been removed]
>
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