Re: Re: hash keys, %

I'd like to thank you two for (blokhead and cleverett) for helping with this tricky problem. Of the two methods posted, I went with blockhead's because it looks a lot easier to understand (even though I won't understand fully what's going on until I take a look at splice in a few minutes).

The code I used is

my @keys  = sort keys %upload;
my $group = 0;

while (my @group = splice(@keys, 0, 20)) {

  $group++;


my $url = "http://sulfericacid.perlmonk.org/gallery/galleryprint2.pl";
  print qq(<a href="$url?page=$group">$group</a><br>\n);

}
[download]

What exactly is being stored in @keys? The total of keys from the hash or all the key/value information from the hash and using this as an easier method to count each of them?

Thanks again for all your help! If you want to see why I needed this, http://sulfericacid.perlmonk.org/gallery/galleryprint2.pl.

"Age is nothing more than an inaccurate number bestowed upon us at birth as just another means for others to judge and classify us"

sulfericacid

Comment on Re: Re: hash keys, % Download Code

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Re: Re: Re: hash keys, % by blokhead (Monsignor) on Jul 29, 2003 at 01:30 UTC
`splice(@keys, 0, 20)` removes the first 20 items from the array `@keys`, but almost as important, it also returns the items it removed. So it's like using `shift` on a larger chunk. You can use `splice` to simulate `push`, `pop`, `shift`, and `unshift`, as well as insert and remove items from the middle of an array. Of course, the man page for `splice` goes over all this in detail, but it's often useful to think of a splice operation in terms of those 4 basic list operators. But I would suggest not even using this loop, since you never actually seem to use the stuff in `@group` that you splice off. You only seem to be interested in the number to print out, so you could just as easily do this: `use POSIX 'ceil'; my $url = "http://..."; my $num_pages = ceil( (keys %hash) / 20 ); print qq(<a href="$url?page=$_">$_</a><br>\n) for 1 .. $num_pages;` [download] Even if you do use this method, you should still get familiar with `splice`! blokhead	[reply] [d/l] [select]

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Re: Re: Re: hash keys, %
by blokhead (Monsignor) on Jul 29, 2003 at 01:30 UTC

splice(@keys, 0, 20)

@keys

shift

splice

push

pop

shift

unshift

splice

But I would suggest not even using this loop, since you never actually seem to use the stuff in @group that you splice off. You only seem to be interested in the number to print out, so you could just as easily do this:

use POSIX 'ceil';
my $url       = "http://...";
my $num_pages = ceil( (keys %hash) / 20 );

print qq(<a href="$url?page=$_">$_</a><br>\n)
    for 1 .. $num_pages;
[download]

splice

blokhead

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