S1Q2 · Card to Value Tuple¶
⚡ Quick Reference
Function: card_to_value_tuple(card: str) -> tuple
Core idea: split the card string into rank and suit, look both up in dicts, return (suit_value, rank_value).
def card_to_value_tuple(card: str) -> tuple:
suit_values = {'S': 1, 'H': 2, 'D': 3, 'C': 4}
rank_values = {'A': 1, 'J': 11, 'Q': 12, 'K': 13}
suit = card[-1] # always last character
rank = card[:-1] # everything before the suit
rank_val = rank_values.get(rank, int(rank))
return (suit_values[suit], rank_val)
Key rules:
- Suit is always the last character: card[-1]
- Rank is everything before the suit: card[:-1]
- Numeric ranks (2–10) convert directly with int()
- Face cards and Ace use a lookup dict; dict.get(rank, int(rank)) handles both cases
Problem Statement¶
Problem
Write a function card_to_value_tuple(card) that takes a card string like "AH" or "10D" and returns a tuple (suit_value, rank_value).
Suit values: S=1, H=2, D=3, C=4
Rank values: A=1, 2–10=face value, J=11, Q=12, K=13
Examples:
'AH'
(2, 1)
'10D'
(3, 10)
'QS'
(1, 12)
Understanding the parsing¶
The card format is {rank}{suit} where suit is always exactly one character at the end. This means:
'AH' → suit = 'H', rank = 'A'
'7D' → suit = 'D', rank = '7'
'10D' → suit = 'D', rank = '10' ← rank can be 2 chars
'QS' → suit = 'S', rank = 'Q'
card[-1] always gives the suit. card[:-1] gives everything before -which is the rank (1 or 2 characters).
dict.get(rank, int(rank)) -handles both cases
Face cards and Ace are in the dict. Numeric ranks are not. rank_values.get(rank, int(rank)) returns the dict value if the key exists, otherwise falls back to int(rank) -converting "7" or "10" to 7 or 10. One expression handles all ranks.
Tracing all examples¶
| Card | card[-1] (suit) |
card[:-1] (rank) |
suit_val | rank_val | Result |
|---|---|---|---|---|---|
'AH' |
'H' |
'A' |
2 | 1 | (2, 1) |
'7D' |
'D' |
'7' |
3 | 7 | (3, 7) |
'QS' |
'S' |
'Q' |
1 | 12 | (1, 12) |
'9C' |
'C' |
'9' |
4 | 9 | (4, 9) |
'10D' |
'D' |
'10' |
3 | 10 | (3, 10) |
Solution approaches¶
def card_to_value_tuple(card: str) -> tuple:
suit_values = {'S': 1, 'H': 2, 'D': 3, 'C': 4}
rank_values = {
'A': 1, '2': 2, '3': 3, '4': 4, '5': 5,
'6': 6, '7': 7, '8': 8, '9': 9, '10': 10,
'J': 11, 'Q': 12, 'K': 13
}
suit = card[-1]
rank = card[:-1]
return (suit_values[suit], rank_values[rank])
Include all ranks in the dict -no int() conversion needed. More explicit, slightly more typing.
def card_to_value_tuple(card: str) -> tuple:
suit_values = {'S': 1, 'H': 2, 'D': 3, 'C': 4}
rank_values = {'A': 1, 'J': 11, 'Q': 12, 'K': 13}
get_rank = lambda r: rank_values.get(r, int(r))
return (suit_values[card[-1]], get_rank(card[:-1]))
The lambda encapsulates the rank-lookup logic cleanly, making the return statement read like a direct mapping.
Key takeaways¶
card[-1] and card[:-1] for fixed-suffix parsing
When the last character is always the delimiter (here, the suit), card[-1] and card[:-1] split it cleanly -no need to know the length upfront. Works for both "AH" and "10D".
dict.get(key, default) for mixed lookups
rank_values.get(rank, int(rank)) handles both named ranks (via dict) and numeric ranks (via fallback conversion) in one expression -no branching needed.
Return order matters -(suit, rank) not (rank, suit)
The problem specifies (suit_value, rank_value). Always double-check the tuple order against the examples -swapping them is an easy mistake that passes visual inspection.