Multidimensional Arrays and Their Traversal in TypeScript

Multidimensional Arrays and Their Traversal in TypeScript | CodeSignal Learn

Topic Overview

Welcome to today's session on "Multidimensional Arrays and Their Traversal in TypeScript" . Multidimensional arrays in TypeScript are similar to those in other programming languages but with the added benefit of type safety. These arrays store arrays at each index instead of single elements, enabling us to create complex data structures that can model various real-life scenarios. Our goal today is to strengthen your foundational knowledge of multidimensional arrays and how to handle them effectively in TypeScript.

Creating Multidimensional Arrays

To construct a multidimensional array in TypeScript, we utilize arrays of arrays, incorporating type annotations to specify data types clearly. Here is an example demonstrating how to create and work with 2D static arrays: TypeScript let array: number[][] = [[1, 2, 3], [4, 5, 6], [7, 8, 9]]; console.log(array); // Outputs: [ [ 1, 2, 3 ], [ 4, 5, 6 ], [ 7, 8, 9 ] ] let array: number[][] = [[1, 2, 3], [4, 5, 6], [7, 8, 9]]; console.log(array); // Outputs: [ [ 1, 2, 3 ], [ 4, 5, 6 ], [ 7, 8, 9 ] ]

Indexing in Multidimensional Arrays

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Traversing Multidimensional Arrays

You can think of the rows as floors and the columns as apartments on each floor. By using nested loops, we can visit every floor (outer array) and every apartment on each floor (inner array) to perform various operations. TypeScript let array: string[][] = [["Apt 101", "Apt 102", "Apt 103"], ["Apt 201", "Exit Floor", "Apt 203"], ["Apt 301", "Apt 302", "Apt 303"]]; // Loop through 2D array for (let i = 0; i < array.length; i++) {for (let j = 0; j < array[i].length; j++) {console.log(array[i][j] + ", ");} console.log();} // Outputs: // Apt 101, // Apt 102, // Apt 103, // // Apt 201, // Exit Floor, // Apt 203, // // Apt 301, // Apt 302, // Apt 303, let array: string[][] = [["Apt 101", "Apt 102", "Apt 103"], ["Apt 201", "Exit Floor", "Apt 203"], ["Apt 301", "Apt 302", "Apt 303"]]; // Loop through 2D array for (let i = 0; i < array.length; i++) {for (let j = 0; j < array[i].length; j++) {console.log(array[i][j] + ", ");} console.log();} // Outputs: // Apt 101, // Apt 102, // Apt 103, // // Apt 201, // Exit Floor, // Apt 203, // // Apt 301, // Apt 302, // Apt 303,

Updating Multidimensional Arrays

To continue with the apartment-building analogy, suppose the task is to replace an apartment number. For example, updating the second apartment number on the first floor (the second element in the first array) can be achieved like this: TypeScript let array: string[][] = [["Apt 101", "Apt 102", "Apt 103"], ["Apt 201", "Apt 202", "Apt 203"], ["Apt 301", "Apt 302", "Apt 303"]]; // Updating an element array[0][1] = "Apt 104"; // Changing "Apt 102" to "Apt 104" for (let i = 0; i < array.length; i++) {for (let j = 0; j < array[i].length; j++) {console.log(array[i][j] + " ");} console.log();} // Outputs: // Apt 101 Apt 104 Apt 103 // Apt 201 Apt 202 Apt 203 // Apt 301 Apt 302 Apt 303 let array: string[][] = [["Apt 101", "Apt 102", "Apt 103"], ["Apt 201", "Apt 202", "Apt 203"], ["Apt 301", "Apt 302", "Apt 303"]]; // Updating an element array[0][1] = "Apt 104"; // Changing "Apt 102" to "Apt 104" for (let i = 0; i < array.length; i++) {for (let j = 0; j < array[i].length; j++) {console.log(array[i][j] + " ");} console.log();} // Outputs: // Apt 101 Apt 104 Apt 103 // Apt 201 Apt 202 Apt 203 // Apt 301 Apt 302 Apt 303

Finding the Number of Rows and Columns

TypeScript allows for managing multidimensional arrays with type safety. You can determine the number of rows (floors) and columns (units on each floor): TypeScript let array: number[][] = [[1, 2, 3], [4, 5, 6], [7, 8, 9]]; // Finding the number of rows let numFloors: number = array.length; console.log(numFloors); // Outputs: 3 // Finding the number of columns let numUnits: number = array[0].length; console.log(numUnits); // Outputs: 3 let array: number[][] = [[1, 2, 3], [4, 5, 6], [7, 8, 9]]; // Finding the number of rows let numFloors: number = array.length; console.log(numFloors); // Outputs: 3 // Finding the number of columns let numUnits: number = array[0].length; console.log(numUnits); // Outputs: 3

Adding a New Row

To add a new row to a 2D array, typically add it at the end. Inserting at specific positions can involve additional operations: TypeScript let array: number[][] = [[1, 2, 3], [4, 5, 6], [7, 8, 9]]; array[3] = [10, 11, 12]; // Adding a new row at the 4th position for (let i = 0; i < array.length; i++) {for (let j = 0; j < array[i].length; j++) {console.log(array[i][j] + " ");} console.log();} // Outputs: // 1 2 3 // 4 5 6 // 7 8 9 // 10 11 12 let array: number[][] = [[1, 2, 3], [4, 5, 6], [7, 8, 9]]; array[3] = [10, 11, 12]; // Adding a new row at the 4th position for (let i = 0; i < array.length; i++) {for (let j = 0; j < array[i].length; j++) {console.log(array[i][j] + " ");} console.log();} // Outputs: // 1 2 3 // 4 5 6 // 7 8 9 // 10 11 12

Removing a Row or Column

To remove a column from a 2D array, directly modify each row using the splice method. TypeScript let array: number[][] = [[1, 2, 3], [4, 5, 6], [7, 8, 9]]; // Removing the second column (index 1) from each row for (let i = 0; i < array.length; i++) {array[i].splice(1, 1); // Remove 1 element at index 1 of each row} for (let i = 0; i < array.length; i++) {for (let j = 0; j < array[i].length; j++) {console.log(array[i][j] + " ");} console.log();} // Outputs: // 1 3 // 4 6 // 7 9 let array: number[][] = [[1, 2, 3], [4, 5, 6], [7, 8, 9]]; // Removing the second column (index 1) from each row for (let i = 0; i < array.length; i++) {array[i].splice(1, 1); // Remove 1 element at index 1 of each row} for (let i = 0; i < array.length; i++) {for (let j = 0; j < array[i].length; j++) {console.log(array[i][j] + " ");} console.log();} // Outputs: // 1 3 // 4 6 // 7 9 To remove a row: TypeScript let array: number[][] = [[1, 2, 3], [4, 5, 6], [7, 8, 9]]; // Removing the second row (index 1) array.splice(1, 1); // Remove 1 element at index 1 of the array for (let i = 0; i < array.length; i++) {for (let j = 0; j < array[i].length; j++) {console.log(array[i][j] + " ");} console.log();} // Outputs: // 1 2 3 // 7 8 9 let array: number[][] = [[1, 2, 3], [4, 5, 6], [7, 8, 9]]; // Removing the second row (index 1) array.splice(1, 1); // Remove 1 element at index 1 of the array for (let i = 0; i < array.length; i++) {for (let j = 0; j < array[i].length; j++) {console.log(array[i][j] + " ");} console.log();} // Outputs: // 1 2 3 // 7 8 9

Topic Overview

Creating Multidimensional Arrays

Indexing in Multidimensional Arrays

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Traversing Multidimensional Arrays

Updating Multidimensional Arrays

Finding the Number of Rows and Columns

Adding a New Row

Removing a Row or Column

Break/Continue in Nested Loops

Lesson Summary