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Adding Items to Arrays

3:26 with Jason Seifer

Now that we know how to create a Ruby array, let's learn a few ways to add items to it.

Code Samples

Create an array:

array = ["milk", "eggs", "bread"]

Add the string "carrots" to the end of the array:

array << "carrots"

Add the string "potatoes" to the end of the array:

array.push("potatoes")

Add the string "celery" to the beginning of the array:

array.unshift("celery") # add to beginning

Add the strings "ice cream" and "pie" to the end of the array:

array += ["ice cream", "pie"]

Add the number 1 to the end of the array:

array << 1

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    Now that we know how to create an array, let's look at how to add things to it. 0:00
    Once we have an array, 0:05
    there are a few different ways of adding items to that array. 0:07
    Let's see how that works now using workspaces. 0:10
    So here's another workspace, and I've created a file called arr_addition.rb. 0:14
    If you want to check out what we did in IRB in the last video, 0:20
    it'll be there in array_creation.rb. 0:23
    So now let's go ahead and check out this file. 0:27
    Here we have our grocery_list array. 0:31
    It contains three items, "milk", "eggs" and "bread". 0:34
    We can see the contents of an array if we run it using a Ruby program file by typing 0:40
    puts, and we can do grocery_list.inspect. 0:44
    And that will print out the contents of the array onto the screen. 0:50
    Let's go ahead and run this file by typing ruby array_addition.rb. 0:56
    Now we can see we have our array. 1:02
    Let's go ahead and add something on to this. 1:06
    So I've just clicked up onto line two and if I want to add on to the grocery list, 1:09
    I could say grocery_list and then two less than signs and add another item. 1:16
    And that will append the item onto the end of the array. 1:24
    Now if I run this, 1:30
    we can see that there is another item at the end of the array called "carrots". 1:31
    Another method of adding something to the end of an array 1:37
    is to use a method called push. 1:42
    So we could say grocery_list and then a dot and then push and 1:45
    then open parenthesis and the word "potatoes". 1:50
    This is getting to be a pretty big grocery list. 1:54
    Now if we print this out, we can see we have "carrots" and 1:58
    "potatoes" at the end of our original array. 2:01
    But what happens if we wanted to add something to the beginning of the array? 2:06
    In that case, we could use the method called unshift. 2:10
    Which, instead of adding something to the end of the array, 2:17
    we'll add it to the beginning. 2:21
    And we'll put "celery" at the beginning of the grocery list 2:24
    because we're eating healthy. 2:27
    Now if we run this, we can see that "celery" is here at the beginning 2:30
    as opposed to "carrots" and "potatoes" 2:35
    which were at the end. 2:37
    If we wanted to we could also use 2:40
    the plus equals operator and add more items onto the array that way. 2:44
    Let's go ahead and get some desserts in here. 2:50
    So we'll add "ice cream" and "pie". 2:53
    And you'll notice that I'm adding another array here. 2:57
    Let's run that and see what happens. 3:01
    and it looks like "ice cream" and 3:04
    "pie" were successfully added to the end of our array. 3:05
    Now, we're not limited to just Strings. 3:10
    We could also add numbers if we wanted as well. 3:14
    Or actually, almost any Ruby type can go in there. 3:17
    Try adding on to your arrays now using WorkSpaces. 3:22

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