Task — Hot day

You are given file with daily temperature record in random order. Write a script to find out the days that were hotter than the previous day.

Examples

Example
Input File: (temperature.txt)
2022-08-01, 20
2022-08-09, 10
2022-08-03, 19
2022-08-06, 24
2022-08-05, 22
2022-08-10, 28
2022-08-07, 20
2022-08-04, 18
2022-08-08, 21
2022-08-02, 25
Output:
2022-08-02
2022-08-05
2022-08-06
2022-08-08
2022-08-10

Analysis

The obvious way to do this is to read the the data into an array such that $input{$date} = $temp, and then with for $date (sort keys @input) we can print the desired output in a single line of code.

Try it 

#!/usr/bin/perl

# Peter Campbell Smith - 2022-09-05
# PWC 181 task 2

use v5.28;
use utf8;
use warnings;

my ($line, %input, $day, $yesterday);

# read the data into %input such that $input{date} = temp
while ($line = <DATA>) {
    $input{$1} = $2 if $line =~ m|(.+), (\d+)|;
}

# check each day against the previous one
$yesterday = 99;
for $day (sort keys %input) {
    say qq[$day was hotter ($input{$day}) than the previous day ($yesterday)] if $input{$day} > $yesterday;
    $yesterday = $input{$day};
}

__DATA__
2022-08-01, 20
2022-08-09, 10
2022-08-03, 19
2022-08-06, 24
2022-08-05, 22
2022-08-10, 28
2022-08-07, 20
2022-08-04, 18
2022-08-08, 21
2022-08-02, 25

Output

2022-08-02 was hotter (25) than the previous day (20)
2022-08-05 was hotter (22) than the previous day (18)
2022-08-06 was hotter (24) than the previous day (22)
2022-08-08 was hotter (21) than the previous day (20)
2022-08-10 was hotter (28) than the previous day (10)