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In this tutorial, we will discuss about 2D arrays in Arduino. We will discuss how to initialize a 2D array and use it to store data.

2D Array Initialization in Arduino

Two-dimensional array initialization is very similar to one-dimensional array initialization. In a two-dimensional array, we have to define the number of rows and columns and then initialize it with some data. For example, see the code below.

void setup() {
  int nRow = 2;
  int nCol = 4;
  int myArray[nRow][nCol] = {{1, 2, 3, 4}, {5, 6, 7, 8}};
}

In the above code, nRowis inta variable of type that defines the number of rows of W in the two-dimensional array. nColis a variable of type intthat defines the number of columns in the two-dimensional array, and myArrayis intan array of type that stores the given intvalues. You can change all these values ​​based on the given data. Note that you can also define other data type arrays in Arduino, such as float. Also, note that during array initialization, you must define the number of rows and columns, or at least the number of columns.

Storing data in a 2D array in Arduino

If you want to store data into a two-dimensional array, you must use two loops. To store data in a two-dimensional array, you must go to each position in the two-dimensional array and store the data there. A two-dimensional array contains many elements, so manually storing data at each position will be time-consuming. To save time, you can use two loops to go to each position and store the given data at a specific position. For example, see the code below.

void setup() {
  int data = 0;
  int myArray[nRow][nCol];
  for (int nr = 0; nr < nRow; nr++) {
    for (int nc = 0; nc < nCol; nc++) {
      myArray[nr][nc] = data++;
    }
  }
}

In the above code, we use two loops to go to each position in the 2d array and store the given data there. In this example, data is a variable with a value of zero, but you can change its value based on the given data. This method will arraystore or replace the data at each position in the 2d.

Replace values ​​in 2D array at specific position in Arduino

If you want to store or replace data in only one location, you only need to use the assignment operator for that specific location. For example, see the code below.

void setup() {
  int nRow = 2;
  int nCol = 4;
  int myArray[nRow][nCol] = {{1, 2, 3, 4}, {5, 6, 7, 8}};
  myArray[nRow][nCol] = 0;
}

In the above code, we replace the values ​​at positions nRowand of the two-dimensional array with .nCol0

Retrieve value at specific position in 2D array in Arduino

If you want to get a value from a specific position in a two-dimensional array, you can use the assignment operator. For example, see the following code.

void setup() {
  int nRow = 2;
  int nCol = 4;
  int myArray[nRow][nCol] = {{1, 2, 3, 4}, {5, 6, 7, 8}};
  int myValue = myArray[nRow][nCol];
}

In the above code, we are retrieving the values ​​at positions nRowand in the two-dimensional array, i.e.nCol8

MatrixMathArduino library for 2D arrays

You can use the MatrixMath library provided in Arduino to perform many operations such as addition, subtraction, multiplication, inverse operations, and printing 2D arrays. Read the documentation of this library for more information and check out the examples here.