Re^2: Common Perl Idioms

[ihb]

An alternative to your &find_first_index that I prefer (for smaller lists) is

    use List::Util 'first';

    sub find_first_index {
        my $target = shift;
        first { $_[$_] eq $target } 0 .. $#_;
    }

    # Simple enough to write inline:

    my $idx = first { $ary[$_] eq $target } 0 .. $#ary;

I don't know about any efficiency issues though.

Update: Fixed a off-by-one bug in the sub and added parenthesis.

ihb

Read argumentation in its context!

[demerphq]

I don't know about any efficiency issues though.

Doesn't look good:

Read more... (2 kB)

           Rate ihb_zip ihb_hit dmq_zip dmq_hit
ihb_zip  8461/s      --     -5%    -44%    -50%
ihb_hit  8869/s      5%      --    -42%    -47%
dmq_zip 15177/s     79%     71%      --    -10%
dmq_hit 16782/s     98%     89%     11%      --

And thats using the XS List::Util implementation from 5.8.2. Theres a lot of overhead in calling the closure, and I think that the range operator isn't lazy in this usage, so it has to manufacture a list of indexes to use.

[BrowserUk]

sub firstIdx { 
    $_[ $_ ] eq $_[ 0 ] and return --$_ for 1 .. @_; 
    return; 
}