*Verrrry* cool examples--especially the 'map' in the first one. Thanks!
Paul 7:26am, Todd W. wrote: > > "Paul Archer" <[EMAIL PROTECTED]> wrote in message > news:[EMAIL PROTECTED] > > Is there any (quick and easy) way to get a reverse range, like (10..1), > > rather than a standard (1..10)? The catch is to *not* use 'reverse'. > > I'm teaching Sun's perl course this week (DTP-250), and we were talking > > about working on arrays. The book had an exercise that had the student > > reverse an array by using pop (or shift, I don't remember). That section > is > > before we talk about 'reverse', and I thought you'd be able to do it like: > > @array[0 .. $#array] = @array[$#array .. 0] > > ...but of course, having the range count down doesn't work. > > > > Paul > > Reverse an array without using reverse(): > > with an array slice and map(): > [EMAIL PROTECTED] trwww]$ perl > @array = ( 1 .. 5 ); > @array = @array[ map abs(), -$#array .. 0 ]; > print( join("\n", @array), "\n" ); > Ctrl-D > 5 > 4 > 3 > 2 > 1 > > using splice(), pop(), and for(): > [EMAIL PROTECTED] trwww]$ perl > @array = ( 1 .. 5 ); > splice( @array, $_, 0, pop @array ) for ( 0 .. $#array ); > print( join("\n", @array), "\n" ); > Ctrl-D > 5 > 4 > 3 > 2 > 1 > > or the C way (but skipping the temporary variable): > [EMAIL PROTECTED] perl]$ perl > @array = ( 1 .. 5 ); > for ( $a = 0, $z = $#array; $a < $z; $a++, $z-- ) { > ( $array[$a], $array[$z] ) = ( $array[$z], $array[$a] ); > # @array[ $a, $z ] = @array[ $z, $a ]; # works too > } > print( join("\n", @array), "\n" ); > Ctrl-D > 5 > 4 > 3 > 2 > 1 > > perl is soooo cool. > > Todd W. > > > -------------------------------------------------------------- "I'll say this about Linux: it's the first time I've seen Unix on the right platform."--Steve Ballmer, president of Microsoft (NB: Microsoft used to own SCO, which did, and still does, produce a Unix for the Intel platform.) -------------------------------------------------------------- -- To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED]
