Hello,
Few Perl questions if you please, regarding the optimal (Perlish) way to do
things.
One constraint though: my code needs to run on old Perls (5.8 and up),
and can only use standard modules (so it doesn't help me if there's a CPAN
module which does exactly what I need - I can't require the users to install
it).
1. How to emulate Python's enumerate() function ?
Given a list, how to make a list of tuples with indexes/values ?
The non-perl way:
my @list = ('A'..'Z');
my @output;
for (my @i = 0; $i < $#list ; ++$i) {
push @output, [ $i, $list[$i] ];
}
Perl way?
my @output = map { [ $i, $list[$i] ] } ( 0 .. $#list ) ;
Is there a cleaner way (I can't use List::MoreUtils::pairwise sadly).
2. Given a hash with string-keys and numeric-values, how to return a list of
the keys,
sorted by the values?
e.g
my %h = ( "hello" => 4,
"world" => 1,
"foo" => 2,
"bar" => 3 )
return:
( "world", "foo", "bar", "hello" )
I came up with:
my @result =
map { $_->[0] }
sort { $a->[1] <=> $b->[1] }
map { [ $_, $h{$_} ] }
keys %h;
Is there a better way?
3. How to automatically use the appropriate "cmp" or "<=>" ?
I have a function that accepts a list.
The list is either all strings, or all numbers.
Half-way through, the function needs to sort the list.
Is there a simple way to know whether to use "cmp" or "<=>" ?
I don't want to duplicate code with two functions, and would prefer to avoid
adding an extra parameter to the function telling it if these are numbers or
strings.
Thanks,
-Assaf
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