Hi,
I have a data file in which each line is an instance of an event (e.g. a
sale). The file contains info about where the event happened (the city,
state, country), the type of event (catalogue, telephone, in-store) and some
other classification data (cash, credit card, indentured labor, firstborn
child).
Data fields are:
timestamp
product_name
geo1 (e.g San Francisco)
geo2 (e.g. California)
geo3 (e.g. usa)
geo4 (West)
type1 (store)
type 2 (cash, etc.)
So, if there were 5 sales in San Francisco, then there will be 5 lines in
the text file.
I want to slurp in the whole file and put it in a hash structure of some
sort so I can count totals within each field.
e.g, print out a total of sales by State or by City or by region. I might
not know how many cities are in the field or how many state. The key will
always be the product_name field.
Do I need to make an array for each field, like this:
while (<$line>) {
($time, $product, etc.) = split(/,/,$line, 8);
push @{ $hash1{$product} }, $geo1;
push @{ $hash1{$product} }, $geo2;
etc.
and then count the number of entries by category later on, when I'm looping
through the appropriate array? (That is, for each "city" in geo1, count
it--5 "San Francisco's" means 5 sales in SF.
I suspect that there's a better structure, which allows me to total the
counts for each field as I load it. And that I can use anonymous arrays to
load in the whole thing once.
I'd very much appreciate any advice.
Best,
Sean
> -----Original Message-----
> From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]]
> Sent: Tuesday, September 18, 2001 3:24 PM
> To: [EMAIL PROTECTED]
> Subject: autovivification of typeglobs
>
>
> Gurus,
> The Camel ( 3rd Ed. ), says, on page 385-386
> sub TIEHANDLE {
> ....
> open my $self, $from, @_ or croak "can't open $from@_:$!";
> ....
> }
>
> and then,
> " ... the my $self furnishes undefined scalar to open, which knows to
> autovivify it into a typeglob. .... " and further mentions
> autovivifying a
> scalar ($$$self), an array (@$$self) etc.
> I have read and reread the above and related typeglob material many times
> but somehow I don't understand what is going on here. If $self is a
> reference then, the above should read $$self, @$self etc. What is the
> extra $ doing in there? Any help in taking apart the above expressions?
> Also, could somebody give any online pointers (: references :), that
> describe Typeglobs, in more detail?
>
> --------- Thanks in advance,
> Atul
>
>
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