Determine whether the map m contains an entry for the key k
m[k] ~= nil
M.Contains (K)
(contains? m k)
#include <map>
bool key_exists = m.contains(k);
bool key_exists = m.count(k) != 0;
bool key_exists = m.find(k) != m.end();
bool keyExists = m.ContainsKey(key)
if (k in m) { }
m.containsKey(k)
Map.has_key?(m, k)
maps:is_key(K, M).
_, ok := m[k]
import qualified Data.Map.Strict as Map
Map.member k m
(/=Nothing) (lookup k m)
_m.has(_k)
m.hasOwnProperty(k)
k in m
import java.util.Map;
(nth-value 1 (gethash k m))
@import Foundation;
if (m[k]) ...
array_key_exists($k, $m)
uses fgl, classes;
m.IndexOf(k) >= 0
exists $m->{$k}
m.has_key?(k)
m.key?(k)
m.include?(k)
use std::collections::HashMap;
m.contains_key(&k)
m.contains(k)
(assoc k m)
m includesKey: k.
If m.ContainsKey(k) Then...
No security, no password. Other people might choose the same nickname.