Functions - Problem Set

These problems will use your knowledge of looping and conditionals, and we will build functions on top of that.

Getting Started

• Fork and clone this repository
• Run npm install to install dependencies
• Solve the problems below in separate files, located in js
• Run node js/nameOfFile.js to execute code

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Problems

1. mean(arr)

Write a function called mean. It should take in an array of numbers and return the average (mean) of all the numbers. Make sure to account for empty arrays!

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2. sillySum(arr)

Write a function that takes an array of numbers, and returns the sum of each number multiplied by its index.

count += (number * index)

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3. numSquare(max)

Create a function called numSquare that will return an array of all perfect square numbers up to and including, but not exceeding a max number. For example:

numSquare(5);
// Prints: 1, 4, 9, 16, 25

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BONUS

letterCount(word)

Write a function that takes a string that finds out how many times a character occurs. For example, the string "apple" would print the following:

a - 1
p - 2
l - 1
e - 1

Hint: There are two parts to this question.

The first is determining the counts of each letter. To do that, loop through each letter, and increment the value to a key in an object. The key should be the letter, the value is the number of times that the letter was encountered. For example { 'a': 1, 'p': 2, 'l': 1, 'e': 1 }.

The second is then printing out the keys and values inside that object. How can you loop through the keys in an object?

Click to Reveal Answer

Try out the for...in loop. Here's the MDN Article on For...In Loops to get you started.

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

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Licensing

1. All content is licensed under a CC-BY-NC-SA 4.0 license.
2. All software code is licensed under GNU GPLv3. For commercial use or alternative licensing, please contact legal@ga.co.