drills.md

Week 2 Drills

Extending Kyrel

It's time to dig a little deeper into the guts of kyrel. The following functionality doesn't exist in the current implementation of the game. Let's add it!

0. is_empty_method - solution

   Create a utility method called isEmpty that checks the current cell for color and returns a boolean.

1. move_right_n_method - solution

   By default moveRight and moveLeft move the kyrel one cell at a time. Modify both methods so that they take an integer as an argument, representing the number of times to move in that direction. (Make sure that the default behavior continues to work too!)

2. move_method - solution

   Refactor your solution to #2 above. Your goal is to create a generic move method tbat takes two arguments: the direction of movement, and the number of steps/movements to take: e.g. move("r", 4).

3. n_cell_rows - solution

   Currently it is only possible to have a 5 cell row in kyrel. Modify the code so that the length of the row can easily be changed by updating a single variable.

HTML Strings - solution

For the following challanges, please use this data object.

0. As a warmup, try to output the following values:

   • the name of the course
   • the first student's id and full name
   • the number of students in the class
   • a list of github usernames

1. Create a function buildGithubLink that transforms a single student's info into an html string, with the following format:

<a href="https://github.com/torvalds">Linus Torvalds</a>

2. Using the function you just built, create a function called renderGithubLinks that takes an array of students and adds their github links to the page.

Extra points if you use built-in Array methods like forEach, map, and join and only insert into the DOM once.

Letter Frequency Counter - solution

Start code w/ tests here

Write a function that counts the number of times each letter occurs in a given string. It should return an object containing the count for each letter.

For example, given the word "apple", letterCount("apple") should return:

{
  a: 1,
  p: 2,
  l: 1,
  e: 1
}

Bonus: Make sure that lower case letters and upper case letters count for the same character. Also, ignore spaces and punctuation.

Merge

Write a function that takes two sorted arrays of numbers and returns a merged array of the sorted numbers. For example:

var arr1 = [3,6,11];
var arr2 = [2,4,5,8,9];

merge(arr1, arr2);
// [2,3,4,5,6,8,9,11]

Before you start: write some tests! Create a series of simple tests that prove you're getting the correct output (and will make your life easier as a developer).