practica 6

;...

(define (mapi f l)
             (cond [(empty? l) '()]
                   [else (cons (f (first l)) (mapi f (rest l)))]))

(define (raices L) (map sqrt L))

;...

(define (pares L) (filter even? L))

(define (shorty Str) (if (< (string-length Str) 5) #t #f))
(define (cortas L) (filter shorty L))

(define (positivos L) (filter positive? L))

;...


(define (check1 v1 v2) (if (and v1 v2) #t #f) )
(define (todos-verdaderos L) (foldr check1 #t L))

(define (check2 v1 v2) (if (or v1 v2) #t #f) )
(define (uno-verdadero L) (foldr check2 #t L))


(define (LUL x y) (+ 1 y) )
(define (cant-elementos L) (foldr LUL 0 L))

;...

(define (prod L) (foldr * 1 L))
(define (pegar L) (foldr string-append "" L))

;...

(define (mult-pos L) (foldr * 1 (filter positive? L)))
(define (sumAbs L) (foldr + 0 (map abs L)) )
(define (check3 X) (if (not (negative? X)) #t #f ) )
(define (raicess L) (map sqrt (filter check3 L)) )