是的，array_key_exists 函数可以用于检查关联数组中是否存在指定的键
<?php
$assoc_array = array(
"name" => "John",
"age" => 30,
"city" => "New York"
);
if (array_key_exists("name", $assoc_array)) {
echo "Key 'name' exists in the associative array.";
} else {
echo "Key 'name' does not exist in the associative array.";
}
?>
在这个例子中，array_key_exists 检查 $assoc_array 是否包含键 “name”。如果存在，它将输出 “Key ‘name’ exists in the associative array.”，否则输出 “Key ‘name’ does not exist in the associative array.”。
