How do I sort a hash key numerically in Perl?

How do I sort a hash key numerically in Perl?

Sort the keys of the hash according to the values

  1. foreach my $name (sort { $planets{$a} <=> $planets{$b} } keys %planets) {
  2. printf “%-8s %s\n”, $name, $planets{$name};
  3. }

Are Perl hashes ordered?

This module implements an ordered hash, meaning that it associates keys with values like a Perl hash, but keeps the keys in a consistent order.

How do I sort in Perl?

Perl | sort() Function sort() function in Perl is used to sort a list with or without the use of method of sorting. This method can be specified by the user in the form of subroutines or blocks. If a subroutine or block is not specified then it will follow the default method of sorting.

What is sort key Perl?

Perl hash sorting – Printing a Perl hash One attribute of the keys function, however, is that the keys are returned in what appears to be a random order. Therefore, you need to use the sort function to sort the keys in alphabetical order to get the desired printout.

Does hashing maintain key order?

Question: Why can’t hash tables preserve the order of keys? Answer: There is no fundamental reason why they can’t. If you knew enough about your problem, you could design an order preserving hash function (i.e., f(k2)< f(k1) whenever k2< k1).

What is ordered hashing?

An ordered hash is a compound data type that contains key-value pairs of different data types, including any mixture of scalars, arrays, structures, pointers, object references, dictionaries, lists, hashes, and other ordered hashes.

What is a Perl scalar?

A scalar contains a single unit of data. It is preceded with a ($) sign followed by letters, numbers and underscores. A scalar can contain anything a number, floating point number, a character or a string.

How do I check the size of a hash in Perl?

$size = keys %my_hash; The variable $size will now contain the number of keys in your Perl hash, which is the size of the hash, i.e., the total number of key/value pairs in the hash.