pwd present working directory
ls list current directory contents
ls -la list current directory contents in long format and show hidden files
man <some unix command> Bring up the manual pages for a command. Type q to exit
| # Long challenge: Based on the following data, | |
| # write code that prints out the customer's total, including estimated | |
| # sales tax, based on the shipping address they entered. | |
| # Your code should work even if the values of the data change. | |
| # Your output should look like this: "Your total with tax is $4455.54." | |
| shopping_cart = [ | |
| {:name => "iPad 2", :price => 499, :quantity => 2}, |
| class Cart | |
| def initialize | |
| @the_cart = [] | |
| end | |
| def add(item, quantity) | |
| @the_cart << { :item => item, :quantity => quantity } | |
| end | |
| def total |
| # Project Euler Problem 2 | |
| # Each new term in the Fibonacci sequence is generated by adding the previous two terms. | |
| # By starting with 1 and 2, the first 10 terms will be: | |
| # 1, 2, 3, 5, 8, 13, 21, 34, 55, 89, ... | |
| # By considering the terms in the Fibonacci sequence whose values do not exceed four million, | |
| # find the sum of the even-valued terms. |
| # If we list all the natural numbers below 10 that are multiples of 3 or 5, we get 3, 5, 6 and 9. The sum of these multiples is 23. | |
| # Find the sum of all the multiples of 3 or 5 below 1000. | |
| sum, i = 0, 0 | |
| while i < 1000 | |
| sum += i if i % 3 == 0 || i % 5 == 0 | |
| i += 1 | |
| end | |
| puts sum # => 233168 |
| # if n is 1, end the method and return empty array | |
| # set var factor = first number in range 2..n | |
| # that has a remainder of 0 when divided by x | |
| # x being the current iteration of 2..n | |
| # put factor var into an array and then call the | |
| # method we are currently in again passing the | |
| # value of n divided by the current value of factor | |
| def prime_factors(n) | |
| return [] if n == 1 |
| def is_prime?(n) | |
| ((2..(Math.sqrt(n)))).each do |i| | |
| return false if n % i == 0 | |
| end | |
| return true | |
| end |
| # A palindromic number reads the same both ways. The largest palindrome made from the product of two 2-digit numbers is 9009 = 91 99. | |
| # Find the largest palindrome made from the product of two 3-digit numbers. | |
| def looped_palindrome(num1,num2=num1) | |
| product = 0 | |
| while num1 > 900 | |
| product = num1 * num2 | |
| return product if product.to_s == product.to_s.reverse | |
| if num2 > 900 | |
| num2 -= 1 |
| class Prescription | |
| # setter for rx_name | |
| def rx_name=(value) | |
| @rx_name = value | |
| end | |
| # setter for patient name | |
| def patient_name=(value) | |
| @patient_name = value | |
| end |