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:
Dart1for (var i = 0; i < 3; i++) { 2 for (var j = 0; j < 3; j++) { 3 print('i = $i, j = $j'); // e.g., "i = 0, j = 0" 4 } 5} 6/* 7Prints: 8i = 0, j = 0 9i = 0, j = 1 10i = 0, j = 2 11i = 1, j = 0 12i = 1, j = 1 13i = 1, j = 2 14i = 2, j = 0 15i = 2, j = 1 16i = 2, j = 2 17*/
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:
Dart1var i = 0; 2while (i < 3) { 3 var j = 0; 4 while (j < 3) { 5 print('i = $i, j = $j'); // e.g., "i = 0, j = 0" 6 j++; 7 } 8 i++; 9} 10/* 11Prints: 12i = 0, j = 0 13i = 0, j = 1 14i = 0, j = 2 15i = 1, j = 0 16i = 1, j = 1 17i = 1, j = 2 18i = 2, j = 0 19i = 2, j = 1 20i = 2, j = 2 21*/
In this instance as well, the inner loop j completes its cycle for each individual iteration of the outer loop i.
To illustrate nested loops, let's examine a two-dimensional (2D) list — essentially a list of lists:
Dart1var matrix = [ 2 [1, 2, 3], 3 [4, 5, 6], 4 [7, 8, 9] 5]; 6 7for (var i = 0; i < matrix.length; i++) { // Iterating over each row. 8 var row = ''; 9 for (var j = 0; j < matrix[i].length; j++) { // Iterating over each element in the row. 10 row += '${matrix[i][j]} '; 11 } 12 print(row); 13} 14/* 15Prints: 161 2 3 174 5 6 187 8 9 19*/
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.
Dart1for (var i = 1; i <= 5; i++) { // The first loop (for) denotes each level of the pyramid. 2 var row = ''; 3 var j = 1; 4 while (j <= i) { // The second loop (while) adds numbers to each level. 5 row += '$j '; 6 j++; 7 } 8 print(row); // Prints each level of the pyramid. 9} 10 11/* 12Prints: 131 141 2 151 2 3 161 2 3 4 171 2 3 4 5 18*/
Bravo! We've successfully uncovered the mechanics of nested loops in Dart. We've examined nested for and while loops, explained practical cases, and practiced with experiential examples. Buckle up and anticipate some practice tasks coming your way! Your challenge is to master these nested loops. Ready to take it up? Forge ahead!