DataWeave programming challenge #2: Rock Paper Scissors game score system
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Other posts from this series:
DataWeave programming challenge #1: Add numbers separated by paragraphs and get the max number
DataWeave programming challenge #2: Rock Paper Scissors game score system
DataWeave programming challenge #3: Count palindrome phrases using the Strings module
DataWeave programming challenge #4: Solve the Tower of Hanoi mathematical puzzle
DataWeave programming challenge #5: Reverse a phrase's words, but keep the punctuation
DataWeave programming challenge #6: Using tail-recursion to get the factorial of a number
DataWeave programming challenge #7: Modify certain values from a JSON structure
DataWeave programming challenge #8: Sum all digits to get a 1-digit number
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In this post:
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This challenge is based on Advent of Code 2022 day 2
Try to solve this challenge on your own to maximize learning. We recommend you refer to the DataWeave documentation only. Try to avoid using Google or asking others so you can learn on your own and become a DataWeave expert!
Input
Consider the following input payload (can be of txt format):
R R
R P
R S
P R
P P
P S
S R
S P
S S
R RExplanation of the problem
Create a DataWeave script to keep your score on a series of Rock Paper Scissors games. The first column is what your opponent chose and the second column is what you chose. Each letter is a representation of the decision made:
R = Rock
P = Paper
S = Scissors
The rules of the game are simple:
Rock defeats Scissors
Paper defeats Rock
Scissors defeat Paper
As per the scoring system, you will have to keep track of whether you won, lost, or if it was a draw. Remember the second column is your choice. Here's how you will be counting the points:
0 points if you lost the round
3 points if the round was a draw
6 points if you won the round
For example,
The first round was R R, which means both your opponent and you chose Rock. This round results in a draw, so 3 points are added.
The second round was R P, which means your opponent chose Rock and you chose Paper. Paper defeats Rock, which means you win this round. 6 points are added.
The third round was R S, which means your opponent chose Rock and you chose Scissors. Rock defeats Scissors, which means you lose this round. 0 points are added.
The final result will be the number of total points you earned in the 10 rounds.
Expected output
In this case, the expected output would be:
30The result for each of the 10 rounds should be:
3
6
0
0
3
6
6
0
3
3
Clues
If you're stuck with your solution, feel free to check out some of these clues to give you ideas on how to solve it!
Clue #1
Using `splitBy "\n"` is the same as using the lines() function from the Strings module
Clue #2
You can use reduce() to keep the score in the accumulator
Clue #3
If you don't want to use reduce, you can use map() to get the points of each round and add the numbers at the end
Clue #4
You can use splitBy() to get your opponent's moves and yours to compare
Clue #5
You can create a variable with the pointing system
Clue #6
The rules can be made of objects in order to extract the points/moves
Clue #7
If you used map() to get the points, you can use sum() to add all the numbers
Clue #8
You can use the `do` operator to create localized variables
Answer
If you haven't solved this challenge yet, we encourage you to keep trying! It's ok if it's taking longer than you thought. We all have to start somewhere ✨ Check out the clues and read the docs before giving up. You got this!! 💙
There are many ways to solve this challenge, but you can find here some solutions we are providing so you can compare your result with us.
Solution #1 - based on Felix Schnabel's solution
%dw 2.0 output application/json import lines from dw::core::Strings var defeats = { R: "S", P: "R", S: "P" } fun getScore(opponent:String, me:String): Number = if (opponent == me) 3 else if (defeats[me] == opponent) 6 else 0 --- sum(lines(payload) map getScore($[0],$[-1]))
Solution #2
%dw 2.0 output application/json var rules = { R: { R: 3, P: 6, S: 0 }, P: { R: 0, P: 3, S: 6 }, S: { R: 6, P: 0, S: 3 } } --- payload splitBy "\n" reduce ((round, score=0) -> do { var arr = round splitBy " " var opponent = arr[0] var me = arr[-1] --- score + rules[opponent][me] })
Solution #3
%dw 2.0 output application/json import lines from dw::core::Strings var rules = { R: { R: 3, P: 6, S: 0 }, P: { R: 0, P: 3, S: 6 }, S: { R: 6, P: 0, S: 3 } } --- lines(payload) map do { var arr = $ splitBy " " --- rules[arr[0]][arr[1]] } then sum($)
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