CODEWITHSUNDEEP
perl
dharmatech
dharmatech

Reputation: 9527

longest_string in CPAN?

This SO page shows how to find the longest string in an array.

Is this functionality available in a CPAN module as something like 'longest_string' for example? Seems odd to have to duplicate that bit of code. Also seems like a generally useful sub.

For comparison, here's an SO page discussing how to do this in Python.

Upvotes: 2

Views: 196

Answers (4)

moritz
moritz

Reputation: 12852

FWIW the Perl 6 solutions is simply:

my $longest = @list_of_strings.max: *.chars

No module necessary :-)

Upvotes: 1

yarian
yarian

Reputation: 6052

Note the description of List::MoreUtils:

List::MoreUtils provides some trivial but commonly needed functionality on lists which is not going to go into List::Util.

The minmax sub in List::MoreUtils will work but compare numerical values, instead of string lengths. However, minmax can be adapted quite easily to instead compare the lengths of its arguments.

sub minmax_stringlength (@) {
    return unless @_;
    my $min = my $max = $_[0];

    for ( my $i = 1; $i < @_; $i += 2 ) {
        if ( length($_[$i-1]) <= length($_[$i]) ) {
            $min = $_[$i-1] if length($min) > length($_[$i-1]);
            $max = $_[$i]   if length($max) < length($_[$i]);
        } else {
            $min = $_[$i]   if length($min) > length($_[$i]);
            $max = $_[$i-1] if length($max) < length($_[$i-1]);
        }
    }

    if ( @_ & 1 ) {
        my $i = $#_;
        if (length($_[$i-1]) <= length($_[$i])) {
            $min = $_[$i-1] if length($min) > length($_[$i-1]);
            $max = $_[$i]   if length($max) < length($_[$i]);
        } else {
            $min = $_[$i]   if length($min) > length($_[$i]);
            $max = $_[$i-1] if length($max) < length($_[$i-1]);
        }
    }

    return ($min, $max);
}

Note, I did not write the above, I merely added length in the comparisons where before the mere number was being compared. Unfortunately I could not test this because I do not know how the AutoLoader works and I kept getting:

Use of inherited AUTOLOAD for non-method List::MoreUtils::minmax_stringlength() is deprecated at script.pl line 9.

So if the OP finds himself using find max very often he could just exercise his license and modify MoreUtils to provide that functionality.

If somebody more knowledgeable could verify that the above would work please do.

Upvotes: 0

Dallaylaen
Dallaylaen

Reputation: 5318

I disagree. Finding the longest string is trivial to implement and not that often needed. If anything, a more general function could probably make its way into (I suppose) List::MoreUtils. Like this: 

my $longest = find_max { length } @array;

where find_max has a (&@) prototype and implements the algorithm from the linked post.

Upvotes: 3

paxdiablo
paxdiablo

Reputation: 882028

I suspect you'll find that CPAN is more for substantial pieces of code (i.e., more than one-liners).

I, for one, would prefer to have CPAN solve my big problems, like database access or various numerical methods and data structures.

Upvotes: 3

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