Forum Discussion
A LAMBDA Word Search Puzzle
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 ) ));
Congratulations on what you have achieved to date. The coding looks neater than I might have expected. I don't know how long it took you to code the method but it will take a while to unravel the approach.
Until such time, some thoughts on SCAN. Given a 2D array to scan, the function works through the entire 2D array row by row, so a strategy that works on one row could work over the entire range. There is a catch, in that some apparent matches might appear due to the string wrapping round rows. To avoid that, one could insert a column of blanks using HSTACK and then apply SCAN. Something similar can be achieved with the latest batch of array shaping functions such as TOCOL.
A different approach would be to use CONCAT to reduce the entire puzzle to a single string and exploit text searches within the Lambda functions. Such a strategy probably works best when there is only a single occurrence of a word to find. In each case, the transposing and reversing of strings is needed.
I will try to take another look and your workbook later.
Thank you for your reply. I spent a couple days on it on and off then dropped it for a few days because I couldn't resolve it with SCAN. I did go through the paces with TOCOL and reducing the letters to a scalar. I didn't feel good about where I was headed. I revisited the task when I thought of how the new Text functions may be helpful by using delimiters, so I played with feeding TEXTSPLIT/TEXTBEFORE/TEXTAFTER a stack of words to delimit on. SergeiBaklan - I need to take some time to study this solution. I've been looking at this puzzle too much lately but will come back to it soon.
The part I couldn't get around with SCAN was achieving something like this (A sample of the first two rows done manually):
The closest I came was getting WAVE and AES (placed in row 2) but the rest that followed was not accurate.