Re: Comparing packed variables

Yes:

use strict;
use warnings;

for my $pair([253, 254], [253, 257]) {
    my $result = pack("S<", $pair->[0]) cmp pack("S<", $pair->[1]);
    print "Little: $pair->[0] cmp $pair->[1] = $result\n";
    $result = pack("S>", $pair->[0]) cmp pack("S>", $pair->[1]);
    print "Big:    $pair->[0] cmp $pair->[1] = $result\n";
    $result = pack("S", $pair->[0]) cmp pack("S", $pair->[1]);
    print "Native: $pair->[0] cmp $pair->[1] = $result\n";
}
[download]

Prints:

Little: 253 cmp 254 = -1
Big:    253 cmp 254 = -1
Native: 253 cmp 254 = -1
Little: 253 cmp 257 = 1
Big:    253 cmp 257 = -1
Native: 253 cmp 257 = 1
[download]

Optimising for fewest key strokes only makes sense transmitting to Pluto or beyond

Comment on Re: Comparing packed variables Select or Download Code

Replies are listed 'Best First'.
Re^2: Comparing packed variables by Jaap (Curate) on Mar 18, 2021 at 10:33 UTC
Ah like that. Is this a bug in Perl? My data is already in native/little endian-ness so i cannot compare it with packed variables?	[reply]
Re^3: Comparing packed variables by GrandFather (Saint) on Mar 18, 2021 at 10:38 UTC
No, it's not a bug. String compare works from lowest memory address (first byte) to highest comparing one byte from each string at a time. Little endian puts the least significant byte in lowest memory so the two lowest bytes are compared first which is exactly backwards to what you want. Optimising for fewest key strokes only makes sense transmitting to Pluto or beyond	[reply]