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History of Idiom 12 > diff from v126 to v127

Edit summary for version 127 by programming-idioms.org:
Restored version 124: For an alternative implementation, please create a new distinct entry
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Version 126

2020-12-16, 22:45:30

Version 127

2020-12-17, 08:06:29

Idiom #12 Check if list contains a value

Check if list contains a value x.
list is an iterable finite container.

Idiom #12 Check if list contains a value

Check if list contains a value x.
list is an iterable finite container.

Variables
list,x
Variables
list,x
Extra Keywords
array vector member membership
Extra Keywords
array vector member membership
Code 
(define (contains? list x)
  (if (null? list) #f
    (if (equal? (car list) x) #t
      (contains? (cdr list) x))))
Code 
(define (contains list x)
        (if (null? list) #f)
        (if (equal? (car list) x) #t)
        (else (contains (cdr list) x))))
Comments bubble
This is a custom implementation, use it if no built-in predicate is available in your Scheme environment.
Comments bubble
This is a custom implementation, use it if no built-in predicate is available in your Scheme environment.
Demo URL
https://repl.it/@ProgIdioms/SteelbluePhonyTerrapin-1
Demo URL
https://repl.it/@ProgIdioms/SteelbluePhonyTerrapin-1