IndyZ has asked for the wisdom of the Perl Monks concerning the following question:

I have an array like: 
@array = ("12 hours", "23 minutes", "17 seconds");

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I am trying to turn this into an English sentence like "12 hours, 23 minutes, and 17 seconds" Not so tough right? The real problem is that I never know how many items are in the list. The best that I could come up with was: 
$last = pop(@array);
$sentence = join ", ", @array;
$sentence .= "," if ($#array > 0);
$sentence .= " and " if ($#array > -1);
$sentence .= "$last";

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This works for anything, except zero elements, which I check for earlier in the block.

I'm sure some of you wizards can see what I cannot. Any help is appreciated.

=IndyZ

Replies are listed 'Best First'.
Re: Sentances from arrays
by merlyn (Sage) on Nov 28, 2000 at 03:24 UTC
    It's probably clearer if you just say what you mean: 
    $sentence =
  @array <= 0 ? "" :
  @array <= 1 ? $array[0] :
  @array <= 2 ? join(" and ", @array) :
  join(", ", @array[0..$#array-1], "and $array[-1]");

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    That's clearer to me, and safe in case you delete or add a case.

    -- Randal L. Schwartz, Perl hacker

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[d/l]
Re: Sentances from arrays
by myocom (Deacon) on Nov 28, 2000 at 03:33 UTC
    Here's what I use:
    sub list_commify {
    if (@_ > 2) {
        join ", ", @_[0..$#_-1], " and $_[-1]"
    } 
    elsif (@_ > 1) {
        "$_[0] and $_[1]"
    } 
    elsif (@_ > 0) {
        $_[0]
    } 
    else {
        ""
    }
}

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[d/l]
      Personally, I don't like if's. In my mind, they make code harder to read by forcing you to think your way through them. While they are appropriate in other cases, in this case I believe merlyn is clearer.

      =IndyZ

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        To each his own, natch. For me, at least, it's easier to parse the if's, since it's more English-like. I can parse it by reading it aloud.

        I find it harder to pronounce the ? : version, though I appreciate its elegance.

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Re: Sentances from arrays
by cwest (Friar) on Nov 28, 2000 at 05:40 UTC 
    my $sentence = join @array > 2 ? ', ' : ' ',
               @array > 1 ? ( @array[0..$#array-1], 'and '.$array[-1] 
+) : @array;

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    --
Casey
   I am a superhero.
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[d/l]
(2501) Re: Sentances from arrays
by 2501 (Pilgrim) on Nov 28, 2000 at 21:15 UTC
    I couldn't help it...it looked like too much fun trying to crunch this code to its smallest form:P
    use strict;
my @foo = ("23 hours","22 minutes","21 seconds","20 miliseconds","0 na
+noseconds");
my $final;
$final?($final =pop(@foo).", $final"):($final =($#foo>1)?"and ".pop(@f
+oo):pop(@foo)) until not @foo;
print "$final\n";

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    update: I removed an extra space in the output string and a wee mistake (it functioned correctly but it was useless code) from a previous attempt
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[d/l]

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