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
In this post:
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):
2456
2
25235
2456
6
54
58795
3
456
76544
0Explanation of the problem
Create a DataWeave script to sum all the digits from the input payload until there's only one digit left.
For example,
123 + 456 = 579
579 is broken down into 5 + 7 + 9 = 21
21 is broken down into 2 + 1 = 3
The final result is 3 because it's a 1-digit number
Expected output
In this case, the expected output would be:
2Clues
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!
Answer
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@armandomejiam
As per your code, the expected output should be 9, but got 0
%dw 2.0 output application/json fun solve(x) = if (sizeOf(x)==1) x else solve((x reduce ((item, accumulator ) -> accumulator + item))) --- solve(payload splitBy('\n'))
after I viewed the simple reduce solution provided by Diksha, I updated my gist to add a "recursive reduce" function. Also, after realizing the "mod 9" solution (thanks Sai Teja) I wrote this simplistic solution: %dw 2.0 import lines from dw::core::Strings output application/json --- (lines(payload) joinBy "") as Number mod 9
output application/json fun singleit(L:Array):Number=singleit(sum(L map singleit($ as Number default $))) fun singleit(X:Null):Number =0 fun singleit(N: Number):Number = if (N==0) 0 else do{var res = (N mod 9) --- if(res==0) 9 else res} fun singleit(Str :Any) : Number =0 --- singleit(payload splitBy "\n")
%dw 2.0 output application/json import lines from dw::core::Strings fun reduceToOneDigit(inputValue) = inputValue match { case d if(d is Number and sizeOf(d) == 1) -> d else -> reduceToOneDigit($ reduce $$ + $) } --- reduceToOneDigit(lines(payload))