Summary of three methods of js 2D array definition and initialization

Method 1: define and initialize directly. You can use
Var _ TheArray = [["0-1", "0-2"], ["1-1", "1-2"], ["2-1 ", "2-2"]

Method 2: Two-dimensional array with unknown length
Copy codeThe Code is as follows:
Var tArray = new Array (); // declare a dimension first
For (var k = 0; k <I; k ++) {// One-dimensional length is I, and I is a variable, which can be changed according to the actual situation

TArray [k] = new Array (); // declare two-dimensional. An element in each one-dimensional Array is an Array;

For (var j = 0; j <p; j ++) {// The number of p that each element array can contain in a one-dimensional array. p is also a variable;

TArray [k] [j] = ""; // initialize the variable here. The initialization here is empty, and the values in it are overwritten with the required values.
}
}

Input the required value to the defined array.
TArray [6] [1] = 5; // You can pass the value of 5 to the array to overwrite the initialization null.

Method 3: before that, the above two methods have problems. method 2, each definition is initialized. Although it can be modified dynamically later, it is still not feasible.

So I tried a method to dynamically pass values to the array.

Ps: array interesting phenomena encountered in practice

We thought that two-dimensional arrays could directly pass in values like the following.
Copy codeThe Code is as follows:
For (var a = 0; a <I; a ++ ){
TArray [a] = (matArray [a], addArray [a]); // matArray [a] and addArray [a] are two arrays, these two arrays are directly transmitted to tArray [].

};

The result is that the value of the next array is received in tArray [a], and the content of matArray [a] is ignored. If you change the position, matArray [a] is behind, the value of addArray [a] is passed in.

Thinking: simple example:
Copy codeThe Code is as follows:
Var a = [1, 2];

Var B = [];

B [0] = a; // pass array a as an element of array B to array B

Alert (B [0] [1]); // 2

The above is the simplest two-dimensional array,

The above example is written in another way:
Copy codeThe Code is as follows:
Var B = [];

B [0] = [1, 2]; // pass the array [1, 2] into array B as an element of array B

Alert (B [0] [1]); // 2

We can see that the above B [0] = [1, 2] is usable.
Copy codeThe Code is as follows:
For (var a = 0; a <I; a ++ ){

TArray [a] = [matArray [a], addArray [a]; Modify () in the preceding example to [] to form a two-dimensional array.

};

Conclusion: method 3:
Copy codeThe Code is as follows:
For (var a = 0; a <I; a ++ ){

TArray [a] = [aArray [a], bArray [a], cArray [a]; you can also add dArray [a], eArray [a]

};

This situation applies to the situation where several arrays are known and combined into a two-dimensional array.