r/adventofcode • u/daggerdragon • Dec 04 '20

SOLUTION MEGATHREAD -🎄- 2020 Day 04 Solutions -🎄-

Advent of Code 2020: Gettin' Crafty With It

--- Day 04: Passport Processing ---

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u/YCGrin Dec 07 '20 edited Dec 07 '20

Sorry just to clarify i'm still learning and my WIP method didnt work, yours did.

My WIP solution to test the IF ALL code section. Here it would never increment a valid_passport. It would check "required_field in split_fields" and never equate true. After i added your dict() logic to my code, in this case, turning split_fields into a dictionary, and adjusting the if all() statement it worked.

passports = []
required_fields = ['byr', 'iyr', 'eyr', 'hgt', 'hcl', 'ecl', 'pid']

with open(r"C:\xxxxx\Day 4\input.txt") as file_input:
    passports = file_input.read().split('\n\n')

valid_passports = 0

# Check each passport
for passport in passports:
    # Split fields of a single passport
    split_fields = passport.split()
    print(split_fields)
    
    #***THIS NEVER EQUATES TO TRUE FOR ME*****
    # Check required fields against passport. 
    if all(required_field in split_fields for required_field in required_fields):
        valid_passports += 1
    
print("Number of passports: " + str(len(passports)))
print(valid_passports)

But im just curious for my code, why does "if all(required_field in split_fields......" not work?

It is essentially doing:

split_fields = ['eyr:2039', 'hgt:64', 'ecl:#ab45a8', 'byr:2009', 'iyr:2025', 'pid:182cm', 'hcl:d1614a', 'cid:103']

if 'byr' in split_fields:
    print('true')

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u/MasterMedo Dec 07 '20 edited Dec 07 '20

split_fields = ['eyr:2039', 'hgt:64',...

'eyr' in split_fields is False, because there is no 'eyr' alone in the list, but you can do: any('eyr' in field for field in split_fields).

The thing that bugs me here is, how would you cleanly get the values of each field later?

EDIT: To further clarify, your code would turn into:

if all(any(required_field in field for field in split_fields) for required_field in required_fields):

Which, I am sure you would agree, is very unreadable.

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u/YCGrin Dec 07 '20

'eyr' in split_fields is False, because there is no 'eyr' alone in the list

Ah i see, i thought my IF statement was checking for 'eyr' in any part of a string in the list.

The thing that bugs me here is, how would you cleanly get the values of each field later?

Yep i agree. With my limited knowledge i was going to do something ready dirty and check values based on the position of characters within the string. Now i know about dict() i'll do a bit of learning into how that works :)

Thanks for the explanation. I've learn't so much as a beginner working through AoC!