Accessing multi-dimensional arrays in JavaScript involves understanding how to navigate through arrays that contain other arrays. Multi-dimensional arrays are essentially arrays of arrays, and you can access their elements using multiple indices. Here's a guide on how to create and access multi-dimensional arrays in JavaScript:
Creating Multi-Dimensional Arrays
- 2D Arrays: A 2D array can be visualized as a table with rows and columns.
// Creating a 2D array
let twoDimensionalArray = [
[1, 2, 3],
[4, 5, 6],
[7, 8, 9]
];
3D Arrays: A 3D array can be visualized as an array of 2D arrays (essentially a cube).
// Creating a 3D array
let threeDimensionalArray = [
[
[1, 2, 3],
[4, 5, 6]
],
[
[7, 8, 9],
[10, 11, 12]
]
];
Accessing Elements in Multi-Dimensional Arrays
Accessing Elements in a 2D Array: To access an element in a 2D array, you use two indices: one for the row and one for the column.
// Accessing the element at row 1, column 2
let element = twoDimensionalArray[1][2]; // Output: 6
Accessing Elements in a 3D Array: To access an element in a 3D array, you use three indices: one for the "depth", one for the row, and one for the column.
// Accessing the element at depth 0, row 1, column 2
let element = threeDimensionalArray[0][1][2]; // Output: 6
Iterating Through Multi-Dimensional Arrays
- Iterating Through a 2D Array:
for (let i = 0; i < twoDimensionalArray.length; i++) {
for (let j = 0; j < twoDimensionalArray[i].length; j++) {
console.log(twoDimensionalArray[i][j]);
}
}
Iterating Through a 3D Array:
for (let i = 0; i < threeDimensionalArray.length; i++) {
for (let j = 0; j < threeDimensionalArray[i].length; j++) {
for (let k = 0; k < threeDimensionalArray[i][j].length; k++) {
console.log(threeDimensionalArray[i][j][k]);
}
}
}
Example Usage
Here is a complete example demonstrating how to create, access, and iterate through a 2D array:
// Creating a 2D array
let matrix = [
[1, 2, 3],
[4, 5, 6],
[7, 8, 9]
];
// Accessing an element
console.log(matrix[1][2]); // Output: 6
// Iterating through the 2D array
for (let i = 0; i < matrix.length; i++) {
for (let j = 0; j < matrix[i].length; j++) {
console.log(matrix[i][j]);
}
}
And for a 3D array:
// Creating a 3D array
let cube = [
[
[1, 2, 3],
[4, 5, 6]
],
[
[7, 8, 9],
[10, 11, 12]
]
];
// Accessing an element
console.log(cube[0][1][2]); // Output: 6
// Iterating through the 3D array
for (let i = 0; i < cube.length; i++) {
for (let j = 0; j < cube[i].length; j++) {
for (let k = 0; k < cube[i][j].length; k++) {
console.log(cube[i][j][k]);
}
}
}
By following these steps, you can effectively create, access, and iterate through multi-dimensional arrays in JavaScript.
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