Hi Chris,
On Mon, 20 Jun 2016 11:28:57 -0600
Chris Fedde <[email protected]> wrote:
> Kenneth,
>
> Below the cut is my example implementation as I understand your
> requirements.
> Note that the "compare" routine uses $a and $b which are "special" to perl
> sort routines.
> Also the compare routine is written for obviousness rather than for brevity
> or elegance.
>
> The return from compare illustrates Shalomi Fish's point about using the
> "||" operator to compose sort fields.
> Descending numeric order is done by reversing the comparison on that sub
> field.
>
Thanks for the illustrative example! I was too lazy to write one.
Regards,
Shlomi Fish
> chris
>
> ----- cut -----
> #!/usr/env/bin perl
>
> use strict;
> use warnings;
>
> my @x = <DATA>;
>
> sub compare {
> my @a = split(/\t/, $a);
> my @b = split(/\t/, $b);
> return $b[0] <=> $a[0] || $a[1] cmp $b[1]
> }
>
> print for (sort {compare} @x);
>
> __DATA__
> 9500 ohzaew
> 5300 dohpha
> 0700 liemah
> 1700 phuhei
> 0200 phuowo
> 1300 ojaeng
> 3900 aebaat
> 4200 dohgha
> 4200 aiyiej
> 6300 ojaeng
> 1600 haequa
> 3100 hupiez
> 3200 ahrieb
> 3600 ohzaew
> 5300 queebe
> 2000 oeyael
> 0200 hahwoo
> 9900 shahye
> 9300 johhir
> 6400 shahye
> 4500 ohfici
> 5500 ahngoh
> 7300 aibove
> 8200 ahrieb
> 9100 ohzaew
> 3100 ohzaew
> 2800 gahnoh
> 0800 aedeng
> 8400 oowaih
> 0300 vouroh
> 1400 shahye
> 0500 ciejee
> 0500 uanahp
> 2100 ophuum
> 1500 aideev
> 6900 aegeuw
> 6300 haequa
> 9300 queebe
> 5400 reogai
> 5000 ophuum
> 1700 aebaat
> 1600 eshida
> 3700 beidae
> 5200 quieki
> 6800 eashoo
> 6800 ohweba
> 2300 apahqu
> 8100 ahghee
> 6700 jooxoj
> 3500 yeiboo
> 2800 chuema
>
>
> On Fri, Jun 17, 2016 at 3:41 PM, Kenneth Wolcott <[email protected]>
> wrote:
>
> > On Fri, Jun 17, 2016 at 2:33 PM, Kenneth Wolcott
> > <[email protected]> wrote:
> > > Hi;
> > >
> > > I'm having trouble understanding the built-in Perl sort with regards
> > > to mixed numbers and strings
> > >
> > > I'm looking at http://perldoc.perl.org/functions/sort.html
> > >
> > > I have an array that I want to have sorted numerically and descending.
> > >
> > > The array is composed of elements that look like the following regex:
> > >
> > > ^\d+\t\[a-zA-Z0-9]+$
> > >
> > > I always have "use strict" at the top of my Perl scripts.
> > >
> > > If I try:
> > >
> > > my @articles = sort {$b <=> $a} @files;
> > >
> > > I get error(s)/warning(s) that the data is not numeric.
> > >
> > > if I try:
> > >
> > > my @articles = sort {$b cmp $a} @files;
> > >
> > > I will get numbers sorted as letters, not numerically.
> > >
> > > I tried to understand the sort perldoc page further down, but did
> > > not grok it at all.
> > >
> > > What I did as a workaround was to implement my own extremely
> > > brute-force sort routine, which works, but is very ugly.
> > >
> > > Since I have very few elements (perhaps as many as a couple dozen),
> > > the inefficiency is immaterial.
> > >
> > > I'd rather that my code be correct, intuitive and elegant (and
> > efficient).
> > >
> > > Thanks,
> > > Ken Wolcott
> >
> > Addendum:
> >
> > It appears that when the sequence of digits is the same length in all
> > instances that the data will be sorted correctly, but when the length
> > of the sequence of the digits is not the same in the entire data set,
> > that is when the sort results will be incorrect.
> >
> > My most current data with this reverse character sort mechanism works
> > correctly, but I'd like it to work in all cases.
> >
> > --
> > To unsubscribe, e-mail: [email protected]
> > For additional commands, e-mail: [email protected]
> > http://learn.perl.org/
> >
> >
> >
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