| Version 1 (modified by , 15 months ago) ( diff ) |
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This code takes a list of lists and splits it into separate groups whenever a sublist starts with the specified symbol. Each group is then added to the result. The result is a list of these grouped sublists.
To solve this problem in Scheme recursively, let's define a recursive function that will process the list of lists and split them into groups whenever a sublist starts with the specified symbol.
### Steps:
- Base Case: If the list of lists is empty, return an empty list.
- Recursive Case:
- If the first sublist starts with the given symbol and the current group is not empty, start a new group.
- Otherwise, continue adding sublists to the current group.
### Scheme Implementation:
Here’s how you can implement this in Scheme:
(define (split-list-of-lists list-of-lists symbol)
(define (split-helper lists current-group result)
(cond
((null? lists)
(if (null? current-group)
result
(append result (list current-group))))
((equal? (caar lists) symbol)
(if (null? current-group)
(split-helper (cdr lists) (list (car lists)) result)
(split-helper (cdr lists) (list (car lists)) (append result (list current-group)))))
(else
(split-helper (cdr lists) (append current-group (list (car lists))) result))))
(split-helper list-of-lists '() '()))
;; Example usage:
(define list-of-lists
'((a 1 2 3)
(b 4 5 6)
(* 7 8 9)
(c 10 11)
(* 12 13)
(d 14 15 16)))
(define symbol '*)
(split-list-of-lists list-of-lists symbol)
### Explanation:
split-list-of-lists: The main function that initializes the recursive process with an emptycurrent-groupandresult.
split-helper:- Base Case: When
listsis empty, ifcurrent-groupis also empty, return theresult. Otherwise, append thecurrent-groupto theresult. - When symbol is encountered: If the current group is not empty, append it to the result and start a new group. If the current group is empty, simply start a new group with the current sublist.
- Else case: Append the current sublist to the
current-groupand continue the recursion.
- Base Case: When
### Example Output:
Running the above code with the example list-of-lists and symbol, you should get:
'(((a 1 2 3) (b 4 5 6)) ((* 7 8 9) (c 10 11)) ((* 12 13) (d 14 15 16)))
This Scheme code recursively processes the list of lists and splits them into groups based on the given symbol.
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