定义和用法
array_key_exists() 函数判断某个数组中是否存在指定的 key,如果该 key 存在,则返回 true,否则返回 false。
语法
array_key_exists(key,array)
参数 描述
key 必需。规定键名。
array 必需。规定输入的数组。
例子
$olympic = array(
'Barcelona'=>1992,
'Atlanta'=>1996,
'Sydney'=>2000,
'Athens'=>2004,
'Beijing'=>2008
);
$city = array(
'Rome',
'Athens',
'Shanghai'
);
foreach($city as $c)
{
if(array_key_exists($c, $olympic))
{
echo $c.'是数组olympic的索引';
echo '
';
echo '
';
}
else
{
echo $c.'不是数组olympic的索引';
echo '
';
echo '
';
}
}
?>
输出:
Rome不是数组olympic的索引
Athens是数组olympic的索引
Shanghai不是数组olympic的索引

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