Re: (CLPM) reorder via swap

Without using swap, we have a slightly less obfuscated and (uninteresting) way...

@array = qw(put these in a different order);
@order = qw(1 3 5 4 2 0);

print reorder(\@array, \@order);

sub reorder() {
   #23456789012345678901234
   map${@_[0]}[$_],@{$_[1]}
}
[download]

Uninteresting as it may be, it might make for a decent golf... Can this be done in fewer strokes?

What if the input were two strings on <STDIN>, separated by a line feed? We then might have something like:

#!/perl -ln0a
map$F[$_],@F[@F/2..$#F]
[download]

Comment on Re: (CLPM) reorder via swap Select or Download Code

Replies are listed 'Best First'.
Re^2: (CLPM) reorder via swap by japhy (Canon) on Aug 17, 2004 at 21:09 UTC
Assuming we want to return a list in the ordered fashion: `sub reorder { #234567890123456 @{+pop}[@{+pop}] }` [download] I'm taking an array slice instead of using `map()`. And we can get even shorter if we call it as `reorder(@elements, \@neworder)`: `sub reorder { #2345678901 @_[@{+pop}] }` [download] _____________________________________________________ Jeff `japhy` Pinyan, P.L., P.M., P.O.D, X.S.: Perl, regex, and `perl` hacker How can we ever be the sold short or the cheated, we who for every service have long ago been overpaid? ~~ Meister Eckhart	[reply] [d/l] [select]
Re^3: (CLPM) reorder via swap by o0lit3 (Friar) on Aug 18, 2004 at 14:54 UTC
Beautiful and elegant... it's simplicity like this that always reminds me why I love this language. But please help me out a little. What is the `+` operator doing here? I know that `@{+pop}` is somehow saying the same as `@{pop()}`, but I'm not sure why. ...And while I'm on the subject, why am I not allowed to simply say `@{pop}` (besides the fact that I've used a split infinitve)?	[reply] [d/l] [select]
Re^4: (CLPM) reorder via swap by japhy (Canon) on Aug 18, 2004 at 14:58 UTC
When you say `@{bareword}`, Perl doesn't do anything to the bareword, and thinks you're just enclosing the variable name in braces. The reason this is useful is when you're printing something like `"the ${n}th time"`, where you want $n, not $nth. The `+` here disambiguates things; it tells Perl that this is not just a "roped-off" variable name, it's an expression to be evaluated. _____________________________________________________ Jeff `japhy` Pinyan, P.L., P.M., P.O.D, X.S.: Perl, regex, and `perl` hacker How can we ever be the sold short or the cheated, we who for every service have long ago been overpaid? ~~ Meister Eckhart	[reply] [d/l] [select]


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