command-line arg, negative hex?
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From: Ben Morrow on 28 Mar 2010 00:35 Quoth "Uri Guttman" <uri(a)StemSystems.com>: > >>>>> "TM" == Tad McClellan <tadmc(a)seesig.invalid> writes: > > TM> if ( $num =~ s/^-// ) { > TM> $sum -= hex $num; > TM> } > TM> else { > TM> $sum += hex $num; > TM> } > > $sum += ( $num =~ s/^-// ? -1 : 1 ) * $num ; > > not sure if the execution order would work. but less redundancy. :) * associates left-to-right, so yes, it would. $num =~ s/(-?)(.*)/$1.hex$2/e; $sum += $num; (...and once again I find myself wanting a /r switch for s/// that returns the result rather than modifying...) Ben
From: Ilya Zakharevich on 28 Mar 2010 01:10 On 2010-03-28, Uri Guttman <uri(a)StemSystems.com> wrote: >>>>>> "TM" == Tad McClellan <tadmc(a)seesig.invalid> writes: > > TM> George <gbeccles(a)verizon.net> wrote: > >> A test I'm running generates 'implicit' hex values. So, "123", not > >> "0x123". For negative values, it just uses (eg) "-123". I would like > >> to sum a set of these on the command line; eg: ' sum.pl 12 34 -10 ' > >> > >> For non-negative values, 'hex()' does what I want. But, it ignores the > >> '-xx' values. > > > TM> if ( $num =~ s/^-// ) { > TM> $sum -= hex $num; > TM> } > TM> else { > TM> $sum += hex $num; > TM> } > > $sum += ( $num =~ s/^-// ? -1 : 1 ) * $num ; > > not sure if the execution order would work. but less redundancy. :) $sum -= ( $num =~ s/^-// or -1 ) * hex $num (I think hex is needed...) 2/3 ;-) Ilya
From: C.DeRykus on 28 Mar 2010 08:41 On Mar 27, 9:09 pm, "Uri Guttman" <u...(a)StemSystems.com> wrote: > >>>>> "TM" == Tad McClellan <ta...(a)seesig.invalid> writes: > ... > > TM> if ( $num =~ s/^-// ) { > TM> $sum -= hex $num; > TM> } > TM> else { > TM> $sum += hex $num; > TM> } > > $sum += ( $num =~ s/^-// ? -1 : 1 ) * $num ; > > not sure if the execution order would work. but less redundancy. :) > For those of us who can't/won't remember op associativity :) perl -MO=Deparse,-p -e '$sum += ( $num =~ s/^-// ? -1 : 1 * $num ;' ($sum += ((($num =~ s/^-//) ? (-1) : 1) * $num)); -e syntax OK -- Charles DeRykus
From: George on 28 Mar 2010 13:01 On Sun, 28 Mar 2010 05:41:44 -0700 (PDT), "C.DeRykus" <derykus(a)gmail.com> wrote: >On Mar 27, 9:09�pm, "Uri Guttman" <u...(a)StemSystems.com> wrote: >> >>>>> "TM" == Tad McClellan <ta...(a)seesig.invalid> writes: >> ... >> >> � TM> � � if ( $num =~ s/^-// ) { >> � TM> � � � � $sum -= hex $num; >> � TM> � � } >> � TM> � � else { >> � TM> � � � � $sum += hex $num; >> � TM> � � } >> >> � � � � $sum += ( $num =~ s/^-// ? -1 : 1 ) * $num ; >> >> not sure if the execution order would work. but less redundancy. :) >> > >For those of us who can't/won't remember op associativity :) > >perl -MO=Deparse,-p -e '$sum += ( $num =~ s/^-// ? -1 : 1 > * $num ;' > >($sum += ((($num =~ s/^-//) ? (-1) : 1) * $num)); >-e syntax OK Thanks to all. I (hope I) would have eventually thought to use a RegEx. But, it would certainly not have been so concise as these. It's just a pleasure to see tight/clever/good code. Much appreciated. George
From: George on 28 Mar 2010 13:09
On Sun, 28 Mar 2010 05:41:44 -0700 (PDT), "C.DeRykus" <derykus(a)gmail.com> wrote: >On Mar 27, 9:09�pm, "Uri Guttman" <u...(a)StemSystems.com> wrote: >> >>>>> "TM" == Tad McClellan <ta...(a)seesig.invalid> writes: >> ... >> >> � TM> � � if ( $num =~ s/^-// ) { >> � TM> � � � � $sum -= hex $num; >> � TM> � � } >> � TM> � � else { >> � TM> � � � � $sum += hex $num; >> � TM> � � } >> >> � � � � $sum += ( $num =~ s/^-// ? -1 : 1 ) * $num ; >> >> not sure if the execution order would work. but less redundancy. :) >> > >For those of us who can't/won't remember op associativity :) > >perl -MO=Deparse,-p -e '$sum += ( $num =~ s/^-// ? -1 : 1 > * $num ;' > >($sum += ((($num =~ s/^-//) ? (-1) : 1) * $num)); >-e syntax OK Thanks to all. I (hope I) would have eventually thought to use a RegEx. But, it would certainly not have been so concise as these. It's just a pleasure to see tight/clever/good code. Much appreciated. George |