Skip to content

Instantly share code, notes, and snippets.

@dustinddoan

dustinddoan/w2d2_checkpoint_dustin.js

Created August 24, 2016 04:01
Show Gist options
  • Save dustinddoan/a971df09ee8741850c2682b244809158 to your computer and use it in GitHub Desktop.
Save dustinddoan/a971df09ee8741850c2682b244809158 to your computer and use it in GitHub Desktop.
Download ZIP
Raw
w2d2_checkpoint_dustin.js
//1. Write a function average that takes two numbers as input (parameters), and returns the average of those numbers.
function average(num1, num2) {
return (num1 + num2) / 2;
}
//2. Write a function greeter that takes a name as an argument and greets that name by returning something along the lines of "Hello, <name>!"
function greeting(name) {
console.log('Hello ' + name + '!');
}
//3. Write the following functions that each accept a single number as an argument:
//even: returns true if its argument is even, and false otherwise.
function isEven(num) {
if (num % 2 === 0) {
return true;
}
return false;
}
//odd: the opposite of the above.
function isOdd(num) {
if (num %2 !== 0) {
return true;
}
return false;
}
//positive: returns true if its argument is positive, and false otherwise.
function isPossitive(num) {
if (num >= 0) {
return true;
}
return false;
}
//negative: the opposite of the above.
function isNegative(num) {
if (num < 0) {
return true;
}
return false;
}
//4. Write a function sayHello that takes a language parameter, and returns "hello" in that language. Make the function work with at least three languages.
function language(para) {
if (para === 'english') {
return 'Hello';
} else if (para === 'french') {
return 'Bonjour';
} else if (para === 'spanish') {
return 'Hola';
}
}
//5. Write a function validCredentials that accepts two parameters: username and password, and returns true if both are long enough, and false otherwise. You can decide what constitutes "long enough".
function validCredentials(username, password) {
if (username.length >= 6 && password >= 10) {
return true;
}
return false;
}
//6. Repeating a String n Times: Let's write a function called repeatString that takes two parameters: a string str, which is the string to be repeated, and count -- a number representing how many times the string str should be repeated, e.g.
function repeatString(str, count) {
var newStr = '';
for (var i = 0; i < count; i++) {
newStr += str;
}
return newStr;
}
repeatString('dog', 0); // => ''
repeatString('dog', 1); // => 'dog'
repeatString('dog', 2); // => 'dog' + 'dog' => 'dogdog'
repeatString('dog', 3); // => 'dog' + 'dog' + 'dog' => 'dogdogdog'
//7. Write a function called average that takes an array of numbers as a parameter and returns the average of those numbers.
function ave(array) {
var average = 0;
var sum = 0;
for (var i = 0; i < array.length; i++) {
sum += array[i];
}
average = sum / (array.length);
return average;
}
//8. Write a function countWords that, when given a string as an argument, returns an object where keys are the words in the string, and values are the number of occurrences of that word within the string:
function countWords(s) {
var words = s.split(' ');
var result = {};
var count = 0;
for (var i = 0; i < words.length; i++) {
var prop = words[i];
if (prop in result) {
count += 1;
result[prop] = count;
} else {
result[prop] = count;
count +=1
}
}
return result;
}
countWords("hello hello"); // => {"hello": 2}
countWords("Hello hello"); // => {"Hello": 1, "hello": 1}
countWords("The quick brown"); // => {"The": 1, "quick": 1, "brown": 1}
HINT: You will want to make use of the string method split. Try \"Hello hello".split(" ") at a console to see how it works.
// Modify countWords to be case insensitive by using the following string method (experiment at a console with it to learn its behavior):
// "HElLo".toLowerCase(); // => ???
function countWords(s) {
var words = s.toLowerCase().split(' ');
var result = {};
var count = 0;
for (var i = 0; i < words.length; i++) {
var prop = words[i];
if (prop in result) {
count += 1;
result[prop] = count;
} else {
result[prop] = count;
count +=1
}
}
return result;
}
// Read about the join method on MDN and use it to implement a function that accepts a string as an argument and returns that string reversed.
function reverse(str) {
var temp = str.split(' ');
var reverseStr = [];
for (var i = str.length - 1; i >= 0; i--) {
reverseStr.push(str[i]);
}
return reverseStr.join(' ');
}
// The function Object.keys returns an array of an object's keys. Experiment with it at the console like this:
// Object.keys({a: 1, b: 2});
Sign up for free to join this conversation on GitHub. Already have an account? Sign in to comment