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Working with Concatenation and Whitespace

4:57

You often need to display a combination of variable values and static pieces of text. In this video, we’ll talk about concatenation, the process of chaining these values together in a chain. We’ll also discuss how PHP, HTML, and the browser deal with whitespace.


Extra Credit

Add a new type of field to the contact form, something like a dropdown field with a label of "Reason for Inquiry" and a few options in it.

Video Transcript

  • 0:00

    Right now, our site visitors can submit a form to our PHP file.

  • 0:04

    A PHP file receives that information and displays it on the page--

  • 0:08

    all three fields in the continuous line of texts.

  • 0:10

    We'll eventually need to send all this information in the body of an email,

  • 0:14

    so let's modify how it looks a little with some texts and some formatting.

  • 0:17

    Open your htdocs directory and the contact-process.php file.

  • 0:22

    Before we echo out the name here, let's echo out some texts to describe the data.

  • 0:31

    I put a space inside the quotation mark there because I want a space

  • 0:34

    between the word name and the value from the variable.

  • 0:38

    We could do the same for the other fields, adding separate

  • 0:41

    echo commands before we echo out a value.

  • 0:43

    However, it is possible to echo out a variable and the string together in one command

  • 0:48

    using what's known as "concatenation."

  • 0:50

    To concatenate two things is to arrange them together in a chain.

  • 0:54

    Let me show you some examples.

  • 0:56

    The concatenation operator in PHP is a period.

  • 1:00

    You can concatenate two static pieces of texts together like this--to echo out ice cream.

  • 1:06

    You can also concatenate two variables together like this--

  • 1:10

    [echo $name $email; >> Randytest.@email.com]

  • 1:12

    You can mix and match these, also concatenating variables and static pieces of text together.

  • 1:19

    While I'm using the echo command with concatenation here,

  • 1:22

    you can also assign a concatenated string to a variable in this manner.

  • 1:27

    Let's combine these two echo statements into one,

  • 1:30

    concatenating the label, name, and the variable.

  • 1:38

    Let's concatenate labels in front of the other two fields also.

  • 1:50

    Save the file and switch back over to the browser,

  • 1:52

    click the back button, and submit the form again.

  • 1:55

    We now have our labels in place.

  • 1:57

    The text is still not that easy to read because it is all on one continuous line,

  • 2:01

    but these labels definitely helped.

  • 2:03

    Next, let's add some line breaks.

  • 2:05

    The echo statements are already on separate lines, but there's no line break

  • 2:09

    in the text that gets echoed out to the browser.

  • 2:11

    We can add line breaks using an escape sequence.

  • 2:14

    You can't exactly type a line break character in the code here, but you can use

  • 2:18

    a sequence of characters that PHP will interpret as a line break.

  • 2:22

    We can add that sequence at the end here, concatenating it to the name variable.

  • 2:27

    Let's add the sequence after email also.

  • 2:32

    Save these files and switch back to the browser again, click back and submit the form again.

  • 2:40

    View the source on the page and you'll be able to see the line breaks.

  • 2:44

    If we wanted line breaks to display in the browser,

  • 2:46

    we would have to use a break tag to achieve that.

  • 2:51

    But since we're going to display this in the plain text email message,

  • 2:54

    we don't need the break tag.

  • 2:56

    What we see when we view the source is what we'll see in the email.

  • 3:01

    There is an HTML element we can use to have the browser display the whitespace.

  • 3:05

    You wouldn't normally use this in a real web page but it's helpful

  • 3:08

    when working with PHP code values.

  • 3:11

    As the pre-formatted text element or PRE tag, we can wrap this whole block

  • 3:16

    of PHP code in a set of PRE tags to see the whitespace in the browser.

  • 3:27

    Before we do view it in the browser though, let's change one last thing.

  • 3:30

    When we send out this email, we're going to need the entire body

  • 3:33

    of the email in a single variable.

  • 3:36

    We can't echo out the variables one at a time like we do on this page.

  • 3:39

    Let's create a new variable called "email body."

  • 3:48

    And we'll set it equal to a blank value to start.

  • 3:51

    Now, instead of echoing out this next line, let's add it to the end of that variable.

  • 3:56

    To do this, we'll assign the email by a variable, a value equal to itself

  • 4:01

    plus the text concatenated to the end.

  • 4:04

    We can modify our code to add the email address and the message lines

  • 4:08

    to our email body variable in the same way.

  • 4:21

    If all the texts for the email body in one variable, let's go ahead

  • 4:24

    and echo it out to the screen for testing.

  • 4:30

    Let's save this file and go back to the browser.

  • 4:32

    Click the back button again and submit the form.

  • 4:37

    There, that looks much better.

  • 4:39

    We can see the real value on our PHP variable, line breaks and all,

  • 4:42

    now that the browser is displaying it inside of our PRE tag.

  • 4:47

    We covered a lot of ground there.

  • 4:49

    We can add concatenation and exploring how whitespace gets treated in different places.

  • 4:52

    I have a quiz for you and then we'll get back to our contact form.

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Instructor

  • Randy Hoyt