Looping with Ruby

Learn to use loops and iterators to automate repetitive tasks.

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Loops & Iterators
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  1. 1

    Sometimes you want to repeat an action in Ruby while a certain condition is true, but you don't know how many times you'll have to repeat that action. A good example would be prompting a user for a...

  2. 2

    Did you see that? The loop printed out the numbers 1 to 10, then stopped. This was because the loop's condition said to continue while [...] was less than 11; since [...] went up by 1 each time...

  3. 3

    The complement to the [...] loop is the [...] loop. It's sort of like a backward [...] : [...] 1. In the example above, we first create a variable [...] and set it to [...] (zero). 2. ...

  4. 4

    We've been using syntax like [...] , which works, but as you'll increasingly find with Ruby, there's always another way. A shortcut is to use an assignment operator. You already know one assign...

  5. 5

    Sometimes you do know how many times you'll be looping, however, and when that's the case, you'll want to use a [...] loop.

  6. 6

    You saw a bit of new syntax in the previous exercise: [...] . What this says to Ruby is: "For the variable [...] in the range [...] to [...] , do the following." The following was to [...] ,...

  7. 7

    Good work! You're ready to build your very own [...] loop.

  8. 8

    So far we've learned one way to repeat an action in Ruby: using loops. As is often the case in Ruby, however, there's more than one way to accomplish a given task. In this case, it's also possible ...

  9. 9

    The [...] keyword can be used to skip over certain steps in the loop. For instance, if we don't want to print out the even numbers, we can write: [...] 1. In the above example, we loop throug...

  10. 10

    Let's say we want to save a range of numbers in a variable. How would we do this? A variable can only hold a single value, right? In Ruby, we can pack multiple values into a single variable using ...

  11. 11

    Great work! You're really getting the hang of this. The [...] iterator is the simplest, but also one of the least powerful. A more useful iterator is the [...] method, which can apply an expre...

  12. 12

    Cool, no? Now it's your turn to take the [...] method for a test drive. [...] 1. In the example above, we create an array called [...] . 2. Then we show two different ways to print each ite...

  13. 13

    The [...] method is like a super compact [...] loop: it can perform a task on each item in an object a specified number of times. For example, if we wanted to print out [...] ten times, we m...

  14. 14

    Okay, training wheels off. Let's see your stuff! [...] 1. In the above example, we create a variable called [...] and set it to [...] . 2. Then, we print out [...] since we execute the loo...

  15. 15

    Good work! [...] In the example above, we wrote the same loop using [...] and using [...] .

  16. 16

    In case you're not picking up on the theme of Ruby having a gajillion ways to do any given task: let's convert our loop yet again. [...] In the above example, we print out [...] by virtue of ...

  17. 17

    Great work! We'll give you a bit of a break from the numbers game. [...] In the example above, we print out [...] since we loop 10 times.

  18. 18

    Finally, let's replace our [...] with the [...] iterator.

  1. 1

    Hiding information is a major part of programming: protecting passwords, establishing secure connections, and securing programs against tampering all rely on controlling access to information. Whi...

  2. 2

    First things first: we'll need to get the user's input.

  3. 3

    Next, we'll want to divide the user's input into individual words. Ruby has a built-in method for this called [...] ; it takes in a string and returns an array. If we pass it a bit of text in par...

  4. 4

    All right! Time to break out our iterators to go through the user's text. [...] The example above just serves as a reminder of using [...] on the [...] array.

  5. 5

    Good! There were two problems with our output, though: we didn't have spaces between our words, and our program didn't actually replace the word we wanted to redact with the word [...] . [...] ...

  6. 6

    Perfect! Feel free to mess around with your redactor to see what sorts of results you get. Think about the following: * What could you do to make sure your redactor redacts a word regardless of wh...

Looping with Ruby

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