Programming-Idioms

History of Idiom 12 > diff from v130 to v131

Edit summary for version 131 by fsoftengine:
[Scheme] Conditionals were semantically incorrect

↷

Version 130

2020-12-29, 22:12:03

Version 131

2021-01-04, 22:16:46

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

Scheme

Scheme

Code

(define (contains list x)
        (if (null? list) #f)
        (if (equal? (car list) x) #t)
        (else (contains (cdr list) x))))

Code

(define (contains list x)
	(cond [(null? list) #f]
		[(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

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History of Idiom 12 > diff from v130 to v131

Version 130

Version 131

Idiom #12 Check if list contains a value

Idiom #12 Check if list contains a value

Variables

Variables

Extra Keywords

Extra Keywords

Code

Code

Comments bubble

Comments bubble

Demo URL

Demo URL

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