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Silver Contributor

Jul 14, 2022

Solved

A LAMBDA Word Search Puzzle

I've created a 15x10 Word Search. I've included a word list (dynamic range) containing words which might be found in the word search. The goal is to then extract those words when they appear in the...

LAMBDA Word Search Puzzle.xlsx24 KB

Jul 16, 2022

Here is one more variant

//------ variant without TEXTJOIN()

reverseColumns=
LAMBDA( data,
    LET(
        n, COLUMNS( data ),
        CHOOSECOLS( data, SEQUENCE(n,,n,-1) )
    ));

reversedText=
LAMBDA( str,
    LET(
        head, LEFT(str),
        tail, RIGHT(str, LEN(str) - 1),
        IF(str = "", "", reversedText(tail) & head)
    ));

isPolindrom=
LAMBDA( text, text = reversedText( text ) );

checkSingleWord=
LAMBDA( str, vector,
    LET(
        getWord, REDUCE("", vector,
            LAMBDA( a,v,
                IF( LEFT(str, LEN(a&v)) = a&v, a&v,
                IF( LEFT(str) = a, v,
                    IF( a = str, a, "" )
                ) ) ) ),
        IF( getWord = str, str, "")
    ));

checkListOfWords=
LAMBDA( wordsVector, vector,
    LET(
        getWords,
            REDUCE("", wordsVector,
                LAMBDA(a,v, VSTACK(a, checkSingleWord( v, vector) ) )
            ),
        IFERROR( FILTER( getWords, getWords <> ""), "" )
    ));

wordsInMatrix=
LAMBDA( data, wordsVector,
    LET(
        k, SEQUENCE( ROWS(data) ),
        scanData, REDUCE(1, k,
            LAMBDA(a,v,
                CHOOSECOLS(
                    IF( v < SEQUENCE(,v,v,-1),
                        a,
                        VSTACK(a, checkListOfWords( Words, CHOOSEROWS(data,v) ) ) ),
                1 )
            )),
        removeFirst, DROP( scanData, 1 ),
        FILTER( removeFirst, removeFirst <> "")
));

wordsInPuzzle=
LAMBDA( data, wordsVector,
    LET(
    allWords, SORT( VSTACK(
        wordsInMatrix( data, wordsVector ),
        wordsInMatrix( reverseColumns( data ), wordsVector ),
        wordsInMatrix( TRANSPOSE( data ), wordsVector ),
        wordsInMatrix( reverseColumns( TRANSPOSE( data ) ), wordsVector )
    )),
    ifPolindroms, MAP(allWords, LAMBDA(v, isPolindrom(v) ) ),
    polindroms, UNIQUE( FILTER(allWords, ifPolindroms)),
    notPolindroms, FILTER(allWords, ifPolindroms -1),
    stack, IF( ISERR(polindroms), notPolindroms, VSTACK( polindroms, notPolindroms ) ),
    SORT( stack )
));

LAMBDA Word Search Puzzle.xlsx22 KB

flexyourdata

Iron Contributor

Aug 01, 2023

Patrick2788 SergeiBaklan PeterBartholomew1 mtarler

I had a go at solving using a lambda I created a while back called ROTATE. It rotates an array by 90 degrees. By stacking the four rotations and joining the text on each row, I think it becomes a case of scanning the "search for" items against the array of rows.

Spent about 10 minutes on this today. I think it works (and quite quickly), but would appreciate your feedback.

Owen

/*
ROTATE
Author: Owen Price
Date: 2022-09-10

Rotates a 2-dimensional array anti-clockwise by 90 degrees. 

This is not the same behavior as TRANSPOSE, which reflects an array on the main diagonal
from top-left to bottom-right.

Inputs:
- arr - the input array
- times - the number of times to rotate by 90 degrees
- [iter] - optional - used as a counter by the recursion

Note: iter should not be used when calling this function from a spreadsheet
*/

ROTATE = LAMBDA(arr,times,[iter],
    LET(
        _times,MOD(times,4),
        IF(_times=0,arr,
            LET(_iter,IF(ISOMITTED(iter),1,iter),
                _cols,COLUMNS(arr),
                _rotated,INDEX(arr,SEQUENCE(1,ROWS(arr)),_cols-SEQUENCE(_cols)+1),
                IF(_iter=_times,_rotated,ROTATE(_rotated,_times,_iter+1))))));

RotatedStacked = IFERROR(VSTACK(Puzzle,ROTATE(Puzzle,1),ROTATE(Puzzle,2),ROTATE(Puzzle,3)),"");

AsRows = BYROW(RotatedStacked,LAMBDA(r,TEXTJOIN("",TRUE,r)));

fnIsFound = LAMBDA(text, OR(NOT(ISERROR(SEARCH(text,AsRows)))));

Search = REDUCE(,table1[Word List:],LAMBDA(a,b,IF(fnIsFound(b),VSTACK(a,b),a)));

Patrick2788

Silver Contributor

Aug 02, 2023

flexyourdata

I like the Rotate Lambda. A nifty bit of recursion! I've tested it on square and non-square matrices, and it never fails.

This is my variant:

RotateM(matrix,turns)
=IF(
    turns = 0,
    matrix,
    RotateM(
        LET(r, ROWS(TRANSPOSE(matrix)), CHOOSEROWS(TRANSPOSE(matrix), SEQUENCE(r, , r, -1))),
        turns - 1
    )
)

RotateM.xlsx25 KB

flexyourdata
Iron Contributor
Aug 03, 2023
Patrick2788

Very neat! I like the way you've used turns-1 to avoid the iter arg. Makes a lot of sense now I see it.

I think I wrote mine before I had a good grasp of CHOOSECOLS. Although I still think it's problematic in some situations where returning single-cell arrays into other functions, what you've done here is really nice.
mtarler
Silver Contributor
Aug 03, 2023
can I ask why you have ROWS(TRANSPOSE(matrix)) instead of COLUMNS(matrix) ?
- Patrick2788
  Silver Contributor
  Aug 03, 2023
  On my first draft of the function, I noticed I wasn't accounting for non-square matrices. The function worked on 1 spin but failed on 2+. I went back and realized the problem was where I pulled R from and how it was a step behind. I used the nesting of ROWS-TRANSPOSE because it's how I anticipated the move in my head, if that makes sense. Recursion is usually not my first go-to and it shows a bit here. I do like how recursive functions can be very concise.