Easy-to-follow video tutorials help you learn software, creative, and business skills.Become a member

Function arguments

From: PHP with MySQL Essential Training

Video: Function arguments

In the last movie, we learned how to define and to call functions. In this movie, we'll get a better understanding about how we go about working with arguments to our functions. Let's create ourselves a new file this, and open up Basic.html. And we'll do Save As, and this one is going to be called functions_arguments.php. Then let's change this up here to be Functions: Arguments. And let's start out with just the basic say_hello_to function that we used in the last movie, which has one argument, word. Right? So we've already worked with arguments before, we've seen one.

Function arguments

In the last movie, we learned how to define and to call functions. In this movie, we'll get a better understanding about how we go about working with arguments to our functions. Let's create ourselves a new file this, and open up Basic.html. And we'll do Save As, and this one is going to be called functions_arguments.php. Then let's change this up here to be Functions: Arguments. And let's start out with just the basic say_hello_to function that we used in the last movie, which has one argument, word. Right? So we've already worked with arguments before, we've seen one.

Here it is, we've defined a variable, word, that we know we're going to pass a value into. We pass in the string, Everyone, to that. And that Everyone gets assigned to word. And that's what's available for use inside the function then. We already know how that works. I just want to show you a slight revision of that. Let's say that we have another variable here called, John Doe. And instead of passing in Everyone. Well we're going to pass in the variable name. So name equals John Doe. Say_hello_to name.

And that gets then passed into the function. And it should say Hello to John Doe. Let's try it. Let's go back to FireFox and instead of Functions Defining, it's going to be Function Arguments. Hello John Doe. Works exactly as we expected. And we're passing in a variable, but a variable is just a reference to a string. So it shouldn't be a surprise to us that this works. But I want you to notice that even though the variable is name outside the function, the function assigns that to the variable word. And word is what it uses inside the function.

These two don't have to match. So don't worry about that. Whatever it has out here. That's the one that exists outside the function. The function has its own sort of contained world of variables. We'll talk more about that a little later on. For now, I just want you to see the two don't have to have a relationship. Now, let's try some functions with more then one argument. If you remember back when we used the built in PHP function str_replace, we had three arguments to it. The first was the string quick, the second was super fast, and the third was a string That we assigned to the variable third.

Now, of course, this is already predefined for us by PHP. But if we were to define our own, it would look something like this. Function, str_replace, and then the three arguments, right, that go with it. And those might be find, replace, and the target. So we're finding one string. We're going to replace it with another string. Adn we're going to do that inside the target string. That's the third one. Now, it doesn't matter what this function does. What the statements are inside of it. What I want you to see here is the relationship between those three when we're defining the function and the three when we're calling the function. Notice that there are always three of them.

That fit each of those spots, and they're always in the same order. That matters when we're having multiple arguments. The order matters, and the number matters. So let's try our own. Let's start down here, I'll create new PHP tags, and let's put in function. We'll call this one, better_hello. And for now, I'll just flush it out like that. All right, so let's have three arguments here to this. This one will be greeting, and then we're going to pass in the target, and then the punctuation which I'll just abbreviate punct.

And then, I can use those three values inside my function as I go about the work of my functions. I'm going to say echo back the greeting. And then let's concatenate that with a space. And then we'll put the target, that's the person that we're greeting. And then followed by, concatenating that with the punctuation. And last of all, put br tag at the end, just to make it look nice, and a semicolon for the whole thing. See how that works? So we have three different ones that we are working with. Now, these don't have to be in this order, we could jumble these around.

The important thing though is that whatever order we define them in, that that's the order we called them in. We must always call it with the same number of arguments and in the same order. So better_hello and then we can now say that our greeting is going to be Hello. We'll say hello to the person that is stored in the variable name. And also, we're going to have our exclamation point as our punctuation. Alright, so let's just try this out and make sure that our three arguments are all working. There we go, we get Hello John Doe again. And of course, it's flexible. We could just as easily have changes from the greeting and the three exclamation points after it.

Right? Greetings John Doe with three exclamation points is what comes back. Now, as I said, we have to have the same number of items but let's try putting in null here for that last item. So we're providing a value. But that value is null. Let's come back over and reload the page and you'll see what it did. It converted null into a string, which is nothing. We could have also just as easily provided an empty string and it would have done the same thing. The important thing is that we have something there in that place. That if we are asking for three things in, when we define it, that we are sending three things whenever we call it.

There has to be agreement there. A little later, we'll talk about how we can set default values for these arguments. So that we don't always have to send the exact same number. But before we do that, I want us to first talk about return values from a function. We'll do that in the next movie.

Show transcript

This video is part of

Image for PHP with MySQL Essential Training
PHP with MySQL Essential Training

131 video lessons · 37752 viewers

Kevin Skoglund
Author

 
Expand all | Collapse all
  1. 4m 8s
    1. Welcome
      1m 0s
    2. Using the exercise files
      3m 8s
  2. 15m 6s
    1. What is PHP?
      3m 52s
    2. The history of PHP
      2m 51s
    3. Why choose PHP?
      4m 10s
    4. Installation overview
      4m 13s
  3. 54m 53s
    1. Overview
      2m 33s
    2. Working with Apache Web Server
      6m 56s
    3. Changing the document root
      7m 24s
    4. Enabling PHP
      6m 16s
    5. Upgrading PHP
      3m 30s
    6. Configuring PHP
      10m 3s
    7. Installing MySQL
      5m 46s
    8. Configuring MySQL
      7m 24s
    9. Text editor
      5m 1s
  4. 31m 25s
    1. Overview
      3m 27s
    2. Installing WampServer
      5m 46s
    3. Finding the document root
      2m 24s
    4. Configuring PHP
      8m 12s
    5. Configuring MySQL
      5m 45s
    6. Text editor
      5m 51s
  5. 19m 12s
    1. Embedding PHP code on a page
      6m 43s
    2. Outputting dynamic text
      5m 55s
    3. The operational trail
      2m 27s
    4. Inserting code comments
      4m 7s
  6. 1h 18m
    1. Variables
      7m 50s
    2. Strings
      4m 38s
    3. String functions
      8m 54s
    4. Numbers part one: Integers
      6m 27s
    5. Numbers part two: Floating points
      5m 25s
    6. Arrays
      10m 0s
    7. Associative arrays
      6m 37s
    8. Array functions
      6m 33s
    9. Booleans
      3m 50s
    10. NULL and empty
      5m 15s
    11. Type juggling and casting
      8m 27s
    12. Constants
      4m 43s
  7. 27m 37s
    1. If statements
      6m 0s
    2. Else and elseif statements
      4m 16s
    3. Logical operators
      7m 30s
    4. Switch statements
      9m 51s
  8. 42m 15s
    1. While loops
      8m 41s
    2. For loops
      5m 59s
    3. Foreach loops
      8m 16s
    4. Continue
      8m 28s
    5. Break
      4m 8s
    6. Understanding array pointers
      6m 43s
  9. 37m 25s
    1. Defining functions
      8m 25s
    2. Function arguments
      5m 32s
    3. Returning values from a function
      7m 33s
    4. Multiple return values
      4m 53s
    5. Scope and global variables
      6m 2s
    6. Setting default argument values
      5m 0s
  10. 20m 18s
    1. Common problems
      3m 47s
    2. Warnings and errors
      8m 36s
    3. Debugging and troubleshooting
      7m 55s
  11. 57m 57s
    1. Links and URLs
      5m 33s
    2. Using GET values
      5m 35s
    3. Encoding GET values
      8m 41s
    4. Encoding for HTML
      9m 26s
    5. Including and requiring files
      7m 40s
    6. Modifying headers
      6m 45s
    7. Page redirection
      6m 43s
    8. Output buffering
      7m 34s
  12. 1h 3m
    1. Building forms
      7m 28s
    2. Detecting form submissions
      5m 59s
    3. Single-page form processing
      7m 57s
    4. Validating form values
      10m 40s
    5. Problems with validation logic
      9m 54s
    6. Displaying validation errors
      7m 23s
    7. Custom validation functions
      6m 28s
    8. Single-page form with validations
      7m 25s
  13. 28m 5s
    1. Working with cookies
      2m 49s
    2. Setting cookie values
      5m 55s
    3. Reading cookie values
      6m 1s
    4. Unsetting cookie values
      4m 51s
    5. Working with sessions
      8m 29s
  14. 48m 39s
    1. MySQL introduction
      6m 43s
    2. Creating a database
      7m 41s
    3. Creating a database table
      7m 42s
    4. CRUD in MySQL
      5m 48s
    5. Populating a MySQL database
      7m 32s
    6. Relational database tables
      6m 40s
    7. Populating the relational table
      6m 33s
  15. 56m 4s
    1. Database APIs in PHP
      4m 51s
    2. Connecting to MySQL with PHP
      7m 45s
    3. Retrieving data from MySQL
      8m 47s
    4. Working with retrieved data
      6m 12s
    5. Creating records with PHP
      6m 58s
    6. Updating and deleting records with PHP
      9m 6s
    7. SQL injection
      3m 5s
    8. Escaping strings for MySQL
      6m 45s
    9. Introducing prepared statements
      2m 35s
  16. 35m 58s
    1. Blueprinting the application
      7m 19s
    2. Building the CMS database
      5m 14s
    3. Establishing your work area
      4m 38s
    4. Creating and styling the first page
      4m 22s
    5. Making page assets reusable
      6m 36s
    6. Connecting the application to the database
      7m 49s
  17. 32m 49s
    1. Adding pages to the navigation subjects
      5m 58s
    2. Refactoring the navigation
      6m 7s
    3. Selecting pages from the navigation
      6m 2s
    4. Highlighting the current page
      5m 26s
    5. Moving the navigation to a function
      9m 16s
  18. 1h 45m
    1. Finding a subject in the database
      9m 48s
    2. Refactoring the page selection
      10m 52s
    3. Creating a new subject form
      6m 55s
    4. Processing form values and adding subjects
      11m 20s
    5. Passing data in the session
      9m 16s
    6. Validating form values
      9m 40s
    7. Creating an edit subject form
      8m 30s
    8. Using single-page submission
      7m 44s
    9. Deleting a subject
      9m 44s
    10. Cleaning up
      10m 37s
    11. Assignment: Pages CRUD
      4m 30s
    12. Assignment results: Pages CRUD
      6m 10s
  19. 39m 26s
    1. The public appearance
      8m 52s
    2. Using a context for conditional code
      11m 37s
    3. Adding a default subject behavior
      6m 9s
    4. The public content area
      5m 51s
    5. Protecting page visibility
      6m 57s
  20. 1h 3m
    1. User authentication overview
      4m 3s
    2. Admin CRUD
      8m 41s
    3. Encrypting passwords
      7m 26s
    4. Salting passwords
      5m 42s
    5. Adding password encryption to CMS
      11m 54s
    6. New PHP password functions
      3m 13s
    7. Creating a login system
      11m 28s
    8. Checking for authorization
      5m 48s
    9. Creating a logout page
      5m 40s
  21. 2m 4s
    1. Next steps
      2m 4s

Start learning today

Get unlimited access to all courses for just $25/month.

Become a member
Sometimes @lynda teaches me how to use a program and sometimes Lynda.com changes my life forever. @JosefShutter
@lynda lynda.com is an absolute life saver when it comes to learning todays software. Definitely recommend it! #higherlearning @Michael_Caraway
@lynda The best thing online! Your database of courses is great! To the mark and very helpful. Thanks! @ru22more
Got to create something yesterday I never thought I could do. #thanks @lynda @Ngventurella
I really do love @lynda as a learning platform. Never stop learning and developing, it’s probably our greatest gift as a species! @soundslikedavid
@lynda just subscribed to lynda.com all I can say its brilliant join now trust me @ButchSamurai
@lynda is an awesome resource. The membership is priceless if you take advantage of it. @diabetic_techie
One of the best decision I made this year. Buy a 1yr subscription to @lynda @cybercaptive
guys lynda.com (@lynda) is the best. So far I’ve learned Java, principles of OO programming, and now learning about MS project @lucasmitchell
Signed back up to @lynda dot com. I’ve missed it!! Proper geeking out right now! #timetolearn #geek @JayGodbold
Share a link to this course

What are exercise files?

Exercise files are the same files the author uses in the course. Save time by downloading the author's files instead of setting up your own files, and learn by following along with the instructor.

Can I take this course without the exercise files?

Yes! If you decide you would like the exercise files later, you can upgrade to a premium account any time.

Become a member Download sample files See plans and pricing

Please wait... please wait ...
Upgrade to get access to exercise files.

Exercise files video

How to use exercise files.

Learn by watching, listening, and doing, Exercise files are the same files the author uses in the course, so you can download them and follow along Premium memberships include access to all exercise files in the library.


Exercise files

Exercise files video

How to use exercise files.

For additional information on downloading and using exercise files, watch our instructional video or read the instructions in the FAQ .

This course includes free exercise files, so you can practice while you watch the course. To access all the exercise files in our library, become a Premium Member.

Are you sure you want to mark all the videos in this course as unwatched?

This will not affect your course history, your reports, or your certificates of completion for this course.


Mark all as unwatched Cancel

Congratulations

You have completed PHP with MySQL Essential Training.

Return to your organization's learning portal to continue training, or close this page.


OK
Become a member to add this course to a playlist

Join today and get unlimited access to the entire library of video courses—and create as many playlists as you like.

Get started

Already a member ?

Become a member to like this course.

Join today and get unlimited access to the entire library of video courses.

Get started

Already a member?

Exercise files

Learn by watching, listening, and doing! Exercise files are the same files the author uses in the course, so you can download them and follow along. Exercise files are available with all Premium memberships. Learn more

Get started

Already a Premium member?

Exercise files video

How to use exercise files.

Ask a question

Thanks for contacting us.
You’ll hear from our Customer Service team within 24 hours.

Please enter the text shown below:

The classic layout automatically defaults to the latest Flash Player.

To choose a different player, hold the cursor over your name at the top right of any lynda.com page and choose Site preferences from the dropdown menu.

Continue to classic layout Stay on new layout
Exercise files

Access exercise files from a button right under the course name.

Mark videos as unwatched

Remove icons showing you already watched videos if you want to start over.

Control your viewing experience

Make the video wide, narrow, full-screen, or pop the player out of the page into its own window.

Interactive transcripts

Click on text in the transcript to jump to that spot in the video. As the video plays, the relevant spot in the transcript will be highlighted.

Thanks for signing up.

We’ll send you a confirmation email shortly.


Sign up and receive emails about lynda.com and our online training library:

Here’s our privacy policy with more details about how we handle your information.

Keep up with news, tips, and latest courses with emails from lynda.com.

Sign up and receive emails about lynda.com and our online training library:

Here’s our privacy policy with more details about how we handle your information.

   
submit Lightbox submit clicked
Terms and conditions of use

We've updated our terms and conditions (now called terms of service).Go
Review and accept our updated terms of service.