Robbie Hatley's Solutions, in Perl, for The Weekly Challenge #347 (“Format Date” and “Format Phone”)

For those not familiar with "The Weekly Challenge", it is a weekly programming puzzle with two parts, with a new pair of tasks each Monday. You can find it here: The Weekly Challenge

The Weekly Challenge for the week of 2025-11-10 through 2025-11-16 is #347. The tasks for challenge #347 are as follows:

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Task 347-1: Format Date
Submitted by: Mohammad Sajid Anwar
You are given a date in the form: 10th Nov 2025. Write a script
to format the given date in the form: 2025-11-10 using the set
below:
@DAYS   = ("1st", "2nd", "3rd", ....., "30th", "31st")
@MONTHS = ("Jan", "Feb", "Mar", ....., "Nov",  "Dec")
@YEARS  = (1900..2100)

Example #1:
Input:  "1st Jan 2025"
Output: "2025-01-01"

Example #2:
Input:  "22nd Feb 2025"
Output: "2025-02-22"

Example #3:
Input:  "15th Apr 2025"
Output: "2025-04-15"

Example #4:
Input:  "23rd Oct 2025"
Output: "2025-10-23"

Example #5:
Input:  "31st Dec 2025"
Output: "2025-12-31"

To solve this problem, I use a "month map" hash to map month names back to numbers.

Robbie Hatley's Perl Solution to The Weekly Challenge 347-1

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Task 347-2: Format Phone Number
Submitted by: Mohammad Sajid Anwar
You are given a phone number as a string. Write a script to
format the given phone number using these rules:
1. Remove all non-digit characters.
2. Group digits into blocks of length 3 from left to right.
3. Handle the final digits (4 or fewer) specially:
   - 0 digits: zero blocks
   - 1 digits: one block of length 1
   - 2 digits: one block of length 2
   - 3 digits: one block of length 3
   - 4 digits: two blocks of length 2
4. Join all blocks with dashes.

Example #1:
Input:  "1-23-45-6"
Output: "123-456"

Example #2:
Input:  "1234"
Output: "12-34"

Example #3:
Input:  "12 345-6789"
Output: "123-456-789"

Example #4:
Input:  "123 4567"
Output: "123-45-67"

Example #5:
Input:  "123 456-78"
Output: "123-456-78"

Example #6:
Input:  "42"
Output: "42"

Example #7:
Input:  ""
Output: ""

To solve this problem, I'll use Perl's "substr" function to splice-off chunks of size 3 from the left while the size of the remainder is greater than 4, then handle the final 0-to-4 digits as described.

Robbie Hatley's Perl Solution to The Weekly Challenge 347-2

That's it for challenge 347; see you on challenge 348!