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Now that we have our contact list entered, it's time to print out a formatted contact list.
Code Written
We write the following code in the video. An explanation of each line follows.
contact_list.each do |contact|
puts "Name: #{contact["name"]}"
if contact["phone_numbers"].size > 0
contact["phone_numbers"].each do |phone_number|
puts "Phone: #{phone_number}"
end
end
puts "-----\n"
end
Code Explanation
contact_list.each do |contact|
The contact_list variable is an array. We iterate over each contact using the each method. The array items are passed in to each iteration of the block as a contact variable.
puts "Name: #{contact["name"]}"
Each item in the array is a hash. First, we print out the contact's name by accessing the value at the name key.
if contact["phone_numbers"].size > 0
It is possible to enter a contact without a phone number. The phone_numbers key is a string which is an array. We check whether or not a contact has any phone numbers by checking whether or not the length of the phone_numbers array is greater than 0.
contact["phone_numbers"].each do |phone_number|
puts "Phone: #{phone_number}"
end
Next, we iterate over each phone number and print it out. This only occurs if there are items in the array.
end
puts "-----\n"
end
Finally, we wrap up our loops.
Final Contact List Program
Our final contact list program looks like this:
def ask(question, kind="string")
print question + " "
answer = gets.chomp
answer = answer.to_i if kind == "number"
return answer
end
def add_contact
contact = {"name" => "", "phone_numbers" => []}
contact["name"] = ask("What is the person's name?")
answer = ""
while answer != "n"
answer = ask("Do you want to add a phone number? (y/n)")
if answer == "y"
phone = ask("Enter a phone number:")
contact["phone_numbers"].push(phone)
end
end
return contact
end
contact_list = []
answer = ""
while answer != "n"
contact_list.push(add_contact())
answer = ask("Add another? (y/n)")
end
puts "---"
contact_list.each do |contact|
puts "Name: #{contact["name"]}"
if contact["phone_numbers"].size > 0
contact["phone_numbers"].each do |phone_number|
puts "Phone: #{phone_number}"
end
end
puts "-----\n"
end
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0:01
Okay, now that we have our contact list all set up,
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0:05
we can go ahead and print it out.
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0:06
Now we're going to do this using iteration.
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0:11
So we'll go ahead and we'll just print a little line to the screen there.
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0:15
Now that we have our contact list, let's go ahead and
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0:19
use the each method to iterate over the contact list.
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0:25
Now a contact list is an array.
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0:29
So that will take one argument here.
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0:33
And instead of calling it item, let's be a little more descriptive and
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0:36
call it contact.
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0:39
So now we're going through each contact.
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0:42
Now remember this is an array, now contact is going to be a hash
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0:47
because that is what gets returned in the add contact method,
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0:52
it's a hash with the keys name and phone numbers.
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0:57
So let's go ahead and print out the person's name.
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1:05
And we do that by saying contact,
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1:07
since that is the current item in the contact list.
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1:11
And then we'll print out the value using the key of name.
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1:17
Now, if this contact has any phone numbers let's print those out too.
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1:29
Now phone numbers is going to be an array, so
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1:32
we'll say if there are any phone numbers, we can print those out.
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1:39
And we'll print those out again using the each method.
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1:53
So for each item in the phone number array here,
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1:57
we'll just print out the phone number.
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2:03
The phone number will be passed in to the phone number variable for
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2:08
each iteration in this phone numbers array.
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2:11
Now you'll notice that we have an each inside of another each.
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2:17
When this happens that is called nested.
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2:21
Finally, let's go ahead and print out another line and
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2:28
a new line character, and that will just visually separate each contact for us.
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2:37
So now that that's all done, let's go ahead and run it and see what happens.
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2:44
What is the person's name?
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2:46
I'll just say it's Jason.
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2:47
Do I want to add a phone number?
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2:48
No.
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2:50
Yes, I wanna add a number.
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2:53
We'll add a phone number of 123 for Nick.
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2:54
When we're done, add another.
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2:58
What's the person's name?
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2:59
We'll say Ryan.
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3:01
Add a phone number, 456.
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3:05
And Ryan has two phones.
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3:11
Now, I don't want to add another.
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3:13
I just want to make sure that this program worked, and there we go.
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3:17
We've gone through and iterated over each name and phone number and
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3:22
printed them out using loops and iteration.
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3:27
Feel free to examine the contact list file and
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3:30
change the y loop maybe to an until loop or even just the loop statement.
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3:37
Can also change the formatting if you'd like.
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3:40
In this course we learned about Ruby loops and iterators and
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3:44
used our knowledge to write a very simple contact list program.
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3:48
Great job, everybody.
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