Task — Split array

You are given list of strings containing 0-9 and a-z separated by space only. Write a script to split the data into two arrays, one for integers and one for letters.

Examples

Example 1
Input: @list = ( 'a 1 2 b 0', '3 c 4 d')
Output: [[1,2,0], [3,4]] and [['a','b'], ['c','d']]

Example 2
Input: @list = ( '1 2', 'p q r', 's 3', '4 5 t')
Output: [[1,2], [3], [4,5]] and [['p','q','r'], ['s'], ['t']]

Analysis

Interestingly the formatting of the output is rather different from the input.

After a couple of false starts I decided that the best strategy was to treat the input simply as a string of characters. The only characters that matter are the digits, letters and commas. I append digits to $first and (single-quoted) letters to $second, in both cases appending ', '. When a comma is encountered in the input I append
'], [' to both $first and $second.

It's then just a case of combining $first and $second and eliminating trailing commas and empty occurrences of [].

Try it 

#!/usr/bin/perl

# Peter Campbell Smith - 2022-09-28
# PWC 184 task 2

use v5.28;
use utf8;
use warnings;

my (@lists, $list, $char, $first, $second, $output, $j);

# inputs
@lists = (qq['a 1 2 b 0', '3 c 4 d'], qq['1 2', 'p q r', 's 3', '4 5 t']);

for $list (@lists) {
    say qq[\nInput:  $list];
    $first = $second = '[';
    
    # loop over characters in list
    while ($list =~ m|(.)|g) {
        $char = $1;
        
        # a digit, append it and a comma to $first
        if ($char =~ m|[0-9]|) {
            $first .= qq[$char,];
            
        # a letter, append it and a comma to $second 
        } elsif ($char =~ m|[a-z]|i) {
            $second .= qq['$char',];
        
        # a comma, append '], [' to both $first and $second
        } elsif ($char eq ',') {
            $first .= '], [';
            $second .= '], [';
        }
    }
    
    # tweaks to eliminate empty [] pairs and convert ,] to ]
    $output = qq([$first]] and [$second]]);
    $output =~ s|,]|]|g;
    $output =~ s|\[],\s*||g;
    say qq[Output: $output];        
}

Output

Input:  'a 1 2 b 0', '3 c 4 d'
Output: [[1,2,0], [3,4]] and [['a','b'], ['c','d']]

Input:  '1 2', 'p q r', 's 3', '4 5 t'
Output: [[1,2], [3], [4,5]] and [['p','q','r'], ['s'], ['t']]