divide by '/'

Anonymous Monk has asked for the wisdom of the Perl Monks concerning the following question:

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(tye)Re: divide by '/' by tye (Sage) on Apr 11, 2001 at 08:08 UTC
Personally, I think I'd just go for: `my @sort= do { local( $^W )= 0; sort {$a<=>$b} @list; }` [download] Those strings in a numeric context will compare properly but would produce warnings so I disable warnings. Also, each strings will only be converted to a number once after which that value will be cached in the SV (scalar value) making later comparisons as fast as is possible in Perl. - tye (but my friends call me "Tye")	[reply] [d/l]
Re: divide by '/' by stephen (Priest) on Apr 11, 2001 at 03:20 UTC
So, if I'm reading this right, you've got a bunch of numbers like so: `64/2829 1/349834 37823/8338 5/989328` [download] And you want them sorted like this: `1/349834 5/989328 64/2829 37823/8338` [download] Here: `sub sortbyfirst { my ($f_a, undef) = split(/\//, $a); my ($f_b, undef) = split(/\//, $b); return $f_a <=> $f_b; } @sorted = sort sortbyfirst @numbers;` [download] Note: Untested. This won't be superfast... If you've got a huge list, or this runs constantly, look into the tye transductor, illustrated here. stephen	[reply] [d/l] [select]
Re: divide by '/' by dws (Chancellor) on Apr 11, 2001 at 04:09 UTC
`@numbers = qw( 1/23 3/45 65/0 6/01 0/100 123/4568 ); @sorted = sort { (split('/', $a))[0] <=> (split('/', $b))[0] } @numbers; print "@numbers\n";` [download] Very embarrassing update: That last line should indeed read `print "@sorted\n";` Thanks to jynx for the /msg.	[reply] [d/l] [select]
Re: Re: divide by '/' by jynx (Priest) on Apr 12, 2001 at 23:19 UTC
Did you mean: `print "@sorted\n";` [download] For that last line? jynx	[reply] [d/l]
Re: Re: Re: divide by '/' by dws (Chancellor) on Apr 13, 2001 at 00:47 UTC
Yup. Stringifying the array automatically uses `$"` (`$LIST_SEPARATOR` if you `use English;`) as a separator. It's a shortcut for saying `print join($", @sorted), "\n";` which, since `$"` defaults to `' '`, is a also a shortcut for `print join(' ', @sorted), "\n";`	[reply] [d/l] [select]
Re: divide by '/' by idnopheq (Chaplain) on Apr 11, 2001 at 03:36 UTC
I went with a split, hash, and sort method. `#!/usr/bin/perl -w # slurped file in @numbers # final outcome in %numHash @numbers = ( "432/205", "905/4578", "623/4568", "1/10009", "10/10005" +); foreach ( @numbers ) { ($key, $value) = split /\//, $_; $numHash{$key} = $value; } # UPDATED foreach $numerator ( sort { $a <=> $b } keys %numHash ) { print $numerator , '/' , $numHash{$numerator} , "\n"; }` [download] TIMTOWTDI Dex p.s. - mine won't handle leading zeros, but the pizza man is en route! UPDATE 0: - forgot my <=>!!!!! Need fud! UPDATE 1: - check out how do i sort hash by key numerically	[reply] [d/l]
Re: divide by '/' by astanley (Beadle) on Apr 11, 2001 at 03:13 UTC
I'm not quite sure what you're saying you need to do...but getting and sorting the numbers should be simple. Just put both into it's own array, ie: `my (@left, @right) = (); foreach (@field) { m/$([0-9]+)\/([0-9]+)$/; my $leftnum = $1; my $rightnum = $2; push(@left, $leftnum); push(@right, $rightnum); }` [download] once you have all the values in seperate arrays - just run the sort function on each. I think that's what you were trying to say....once they're sorted you can put them back together or do whatever else you wish to do to them. -Adam Stanley Nethosters, Inc.	[reply] [d/l]
Re: divide by '/' by cLive ;-) (Prior) on Apr 11, 2001 at 04:51 UTC
Update: Oops, just realised that my reply was exactly the same as the one by [id://dws] above. weird... cLive ;-)	[reply]