• Haskell

x `elem` list

• Haskell

find _ [] = False
find n (x:xs)
  | x == n = True
  | otherwise = find n xs

• Ada

Result := List.Contains (X);

• C

bool contains(int x, int* list, size_t list_len) {
    for (int i=0 ; i<list_len ; i++)
        if (list[i] == x)
            return true;
    return false;
}

• Caml

List.mem x list

• Clojure

(some (partial = x) list)

• Clojure

(some #{x} list)

• C++

auto contains(auto list, auto x) -> bool {
  return std::ranges::find(list, x) != std::ranges::end(list);
}

• C++

bool Contains(const std::vector<int> &list, int x)
{
	return std::find(list.begin(), list.end(), x) != list.end();
}

• C#

list.Contains(item);

• D

bool here = canFind(items, x);

• Dart

list.contains(x);

• Elixir

x in list

• Elixir

Enum.member?(list, x)

• Erlang

lists:member(X, List).

• Erlang

member(_, []) -> false;
member(Value, [H|_]) where Value =:= H -> true;
member(Value, [_|T]) -> member(Value, T).

• Erlang

member(_, []) -> false;
member(Value, [H|T]) -> 
  case H of
    Value -> true;
    _ -> member(T)
  end.

• Fortran

if (findloc (list, x, 1) != 0) then

• Fortran

if (any(x == list)) ...

• Go

func Contains(list []T, x T) bool {
	for _, item := range list {
		if item == x {
			return true
		}
	}
	return false
}

• Go

slices.Contains(list, x)

• Groovy

list.contains(x)

• JS

return list.indexOf(x) !== -1;

• JS

return list.includes(x);

• Java

list.contains(x)

• Java

boolean <T> contains(T[] list, T x){
  if( x==null){
    for(T y:list)
      if( y==null )
        return true;
  }else{
    for(T y:list)
      if( x.equals(y) )
        return true;
  }
  return false;
}

• Java

boolean contains(int[] list, int x){
  for(int y:list)
    if( y==x )
      return true;
  return false;
}

• Java

asList(list).contains(x);

• Kotlin

list.contains(x)

• Kotlin

x in list

• Lisp

(find x list :test #'equal)

• Lisp

(member x list)

• Lua

function contains(list, x)
	for _, v in ipairs(list) do
		if v == x then return true end
	end
	return false
end

• Obj-C

[list containsObject:x];

• PHP

in_array($x, $list, true);

• Pascal

result := false;
for e in list do 
	if e=x then
		begin
			result := true;
			break;
		end

• Pascal

result := list.IndexOf(x) <> -1;

• Pascal

p := list;
while (p <> nil) and (p^.key = x) do p := p^.next;
found := p.key = x

• Perl

print "ok\n" if first {$_ eq $x} @list;

• Perl

print "Found 'foo'\n" if grep {$_ eq $x} @list;

• Prolog

member(X, [One]).

• Python

x in list

• Ruby

list.include? x

• Rust

(&list).into_iter().any(|v| v == &x)

• Rust

list.contains(&x);

• Rust

list.iter().any(|v| v == &x)

• Rust

list.binary_search(&x).is_ok()

• Scala

list.contains(x)

• Scheme

(member x list)

• Scheme

(define (contains list x)
	(cond [(null? list) #f]
		[(equal? (car list) x) #t]
		[else (contains (cdr list) x)]))

• Smalltalk

list includes: x.

• VB

List.Contains(x)