Initialization of Arrays with Default Values

Question

Initialization of Arrays with Default Values

I have taken on the task of converting a C++ program into JavaScript.

In C++, when creating a dynamic array of type float/double, the entries are automatically initialized to 0.0; there is no need for explicit initialization.

For example, a 1-D vector of size 3 would appear as (0.0 0.0 0.0)T, with T indicating the transpose of the vector.

A 3 x 3 matrix would be initialized as:

[0.0 0.0 0.0;
0.0 0.0 0.0;
0.0 0.0 0.0]

This feature in C++ streamlines the code and enhances program efficiency by avoiding unnecessary repetition.

Is there a similar functionality in JavaScript? If not, I will resort to explicit initialization:

For instance, Code:

for (let i = 0; i < N; ++i) {
    v[i] = 0.0;
}

Alternatively, can someone suggest the most efficient method for initializing 1-D and 2-D arrays to 0.0 in JavaScript?

javascript arrays

Answer 1

Answer №1

One option with ES6 is to utilize Array#fill.

By using var array = Array(3).fill(0);
//                ^           specifies the size of the array
//                        ^   defines the value of each element

For ES5, you can achieve this as follows:

var array = Array.apply(null, { length: 3 }).map(function () { return 0; });
//                                      ^                                    determines the length of the array
//                                                                    ^      sets the value for each element

Answer 2

One option with ES6 is to utilize Array#fill.

By using var array = Array(3).fill(0);
//                ^           specifies the size of the array
//                        ^   defines the value of each element

For ES5, you can achieve this as follows:

var array = Array.apply(null, { length: 3 }).map(function () { return 0; });
//                                      ^                                    determines the length of the array
//                                                                    ^      sets the value for each element

Initialization of Arrays with Default Values

Answer №1

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