Mastering Nested Loops in Dart

Introduction

Our journey today delves into the intricate world of Exploring Nested Loops in Dart . Think of these as interlocking cogs within a mechanism, each managing its distinct movement. By the end of this session, we aim to understand and adeptly navigate these loops in Dart.

We begin by revealing the structure of a nested for loop in Dart: Dart for (var i = 0; i < 3; i++) {for (var j = 0; j < 3; j++) {print('i = $i, j = $j'); // e.g., "i = 0, j = 0"}} /* Prints: i = 0, j = 0 i = 0, j = 1 i = 0, j = 2 i = 1, j = 0 i = 1, j = 1 i = 1, j = 2 i = 2, j = 0 i = 2, j = 1 i = 2, j = 2 */ With each progression of i from 0 to 2, we traverse through j from 0 to 2, notating the respective values of i and j .

In addition to for loops, while loops can also incorporate nested loops: Dart var i = 0; while (i < 3) {var j = 0; while (j < 3) {print('i = $i, j = $j'); // e.g., "i = 0, j = 0" j++;} i++;} /* Prints: i = 0, j = 0 i = 0, j = 1 i = 0, j = 2 i = 1, j = 0 i = 1, j = 1 i = 1, j = 2 i = 2, j = 0 i = 2, j = 1 i = 2, j = 2 */ In this instance as well, the inner loop j completes its cycle for each individual iteration of the outer loop i .

To illustrate nested loops, let's examine a two-dimensional (2D) list — essentially a list of lists: Dart var matrix = [[1, 2, 3], [4, 5, 6], [7, 8, 9]]; for (var i = 0; i < matrix.length; i++) { // Iterating over each row. var row = ''; for (var j = 0; j < matrix[i].length; j++) { // Iterating over each element in the row. row += '${matrix[i][j]} ';} print(row);} /* Prints: 1 2 3 4 5 6 7 8 9 */ var matrix = [[1, 2, 3], [4, 5, 6], [7, 8, 9]]; for (var i = 0; i < matrix.length; i++) { // Iterating over each row. var row = ''; for (var j = 0; j < matrix[i].length; j++) { // Iterating over each element in the row. row += '${matrix[i][j]} ';} print(row);} /* Prints: 1 2 3 4 5 6 7 8 9 */ For every i row in the outer loop, an inner loop runs through every element within that row.

Now let's explore how to combine a for loop with a while loop to construct a numerical pyramid. This example demonstrates the adaptability of nested loops in Dart and how they can be seamlessly integrated. Dart for (var i = 1; i <= 5; i++) { // The first loop (for) denotes each level of the pyramid. var row = ''; var j = 1; while (j <= i) { // The second loop (while) adds numbers to each level. row += '$j '; j++;} print(row); // Prints each level of the pyramid.} /* Prints: 1 1 2 1 2 3 1 2 3 4 1 2 3 4 5 */ for (var i = 1; i <= 5; i++) { // The first loop (for) denotes each level of the pyramid. var row = ''; var j = 1; while (j <= i) { // The second loop (while) adds numbers to each level. row += '$j '; j++;} print(row); // Prints each level of the pyramid.} /* Prints: 1 1 2 1 2 3 1 2 3 4 1 2 3 4 5 */

Be a part of our community of 1M+ users who develop and demonstrate their skills on CodeSignal