Skip to content

Latest commit

 

History

History
48 lines (33 loc) · 1.9 KB

exercises_a.md

File metadata and controls

48 lines (33 loc) · 1.9 KB

Challenge set A: Array iterators

###Challenge 1 (maps)###

Elaine the Etsy Merchant thinks her prices are scaring off customers. Subtracting one penny might help: Help her out:

var prices = [3.00,4.00,10.00,2.25,3.01];
prices.map(callbackfn);
//[2.99, 3.99, 9.99, 2.24, 3.00]

More Challenges:

  • On second thought, Elaine only wants to subtract a penny if it changes the dollars place, e.g.: 10.00 --> 9.99

  • Prices are going up! Elaine needs to raise her prices by 5%.

###Challenge 2 (filter)### Is there an interesting trend in birthdays? Do people tend to be born more on even-numbered dates or odd-numbered dates? This is a great chance to do some serious science!

var birthDates = [1, 1, 2, 4, 7, 4, 12, 30,...];
birthdates.filter(callbackfn);
evenBirthdates = [2, 4, 4, 12, 30];

  • In an organized and semi-nonchaotic fashion, create a master list of all birthdates with every person in the class. We're only interested in the birthdate (1 - 31), we don't care about month or year.

  • Independently write a filter array function that creates an array for either odd or even birth dates.

  • Compare the results for even numbers with those for odd numbers. Write some code that reports the results. For example 6 out of 10 students were born on an even day. Evens are more common. Or 60% of the class was born on an even-numbered day.

  • Share your results with the class and bask in your great science!

###Challenge 3 (reduce)### Goyle has a lucrative dog walking business. He's made mucho moolah this summer. How much did he make?

var earnings = [20, 25, 60, 20, 85, 20];
earnings.reduce(callbackfn);
// 210

Challenge:

  • Goyle already has $500 in the bank. How would you incorporate this into your method call? (YOU ARE NOT ALLOWED TO USE output + 500)
  • BONUS: Goyle's curious how many times he earned $20 this summer. (HINT: there's a method for this!)