list - 方案语言 : merge two numbers

Question

如何将列表中的两个整数合并为一个？ (在方案中)
例子:
'(11 223) -> 11223

Answer 1

假设列表正好有两个元素，并且都是数字:

(define (merge-numbers lst)
  (let ((1st (number->string (first  lst)))
        (2nd (number->string (second lst))))
    (string->number (string-append 1st 2nd))))

它按预期工作:

(merge-numbers '(11 223))
> 11223

或者，不使用 let :

(define (merge-numbers lst)
  (string->number
   (string-append
    (number->string (first  lst))
    (number->string (second lst)))))