DataWeave programming challenge #5: Reverse a phrase's words, but keep the punctuation
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:
This challenge is based on Codeacademy's Reverse Words challenge
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):
Hello world
May the Fourth be with you
Hello world!
With you, be May the Fourth
With you, be May the Fourth!Explanation of the problem
Create a DataWeave script that will reverse the order of each one of the words in a phrase to form a new phrase. Each phrase or sentence is separated by a new line. Each word is separated by a space. However, the punctuation signs (! and ,) will have to stay in the same place. Lower/upper cases can be kept as-is.
For example:
"Hello world!" becomes "world Hello!"
"With you, be May the Fourth!" becomes "Fourth the, May be you With!"
Expected output
In this case, the expected output would be:
[
"world Hello",
"you with be Fourth the May",
"world Hello!",
"Fourth the, May be you With",
"Fourth the, May be you With!"
]ℹ️ Note: You can keep the output as a JSON or as a text, whatever your preference is.
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
Keep the index of each punctuation sign so you can insert it there later
Clue #2
You can use the isAlphanumeric function from the Strings module
Clue #3
You can use the scan function to separate each phrase in an Array of Strings
Clue #4
You can use the joinBy function to transform from Array to String
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 my solution. I'm sure you all can make it better! :) Mine is super long 😂
Solution #1
%dw 2.0
import slice from dw::core::Arrays
import lines, isAlphanumeric from dw::core::Strings
output application/json
---
lines(payload)
map ((line) -> flatten(
line scan /[^\w\d\s]|[\w]*/
) filter (!isEmpty($)))
map ((words) -> do {
var wordsobj = (words map {
word: $,
originalIndex: $$,
move: isAlphanumeric($)
})
var reversed = (wordsobj filter ($.move))[-1 to 0]
var spechars = wordsobj filter (not $.move)
var endingStr = if (spechars[-1].originalIndex != null)
(reversed[spechars[-1].originalIndex to -1].word default [] joinBy " ")
else ""
---
if (isEmpty(spechars)) reversed.word joinBy " "
else spechars map ((charobj,coidx) ->
slice(
reversed,
if (coidx-1 >= 0) spechars[coidx-1].originalIndex else 0,
charobj.originalIndex
).word joinBy " "
then trim("$($)$(charobj.word) $(endingStr)")
) joinBy " "
})
I also recorded myself coming up with the solution, but without explanations. Just some lo-fi music and a screen :) you can leave the video in the background while working! :D let me know if you find this useful.
Feel free to comment your code below for others to see! 😄
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