js怎么访问数组

let arr = ['apple', 'banana', 'cherry'];
console.log(arr[0]); // 输出: apple
console.log(arr[1]); // 输出: banana
console.log(arr[2]); // 输出: cherry

let arr = ['apple', 'banana', 'cherry'];
for (let i = 0; i < arr.length; i++) {
    console.log(arr[i]);
}

let arr = ['apple', 'banana', 'cherry'];
arr.forEach(function(item) {
    console.log(item);
});

let arr = ['apple', 'banana', 'cherry'];
console.log(arr[3]); // 输出: undefined

let matrix = [
    [1, 2, 3],
    [4, 5, 6],
    [7, 8, 9]
];
console.log(matrix[0][1]); // 输出: 2