I am very Stuck :(

Concatenation joins two things together.

For instance I could concatenate the results of a function or the value of a variable with a string

//Let's get the day of the week
$dayOfWeek = date( 'l' );
//This will get a value of "Monday, Tuesday, Wednesday...etc depending on the day of the week it actually is

echo "Howdy stranger, today is " . $dayOfWeek . ".";

Today, this would output: Howday stranger, today is Wednesday.

The period mark indicates a concatenation.

Peter, Kevin,

Going a little bit beyond the concatenation discussion; while concatenation is really useful, I want to point out the difference between single quotes and double quotes when dealing with variables. Take a look at the following code:

<?php

$var = 'foo';
echo 'The value of variable var is $var.';
echo "The value of variable var is $var.";

?>

The first echo statement will be: The value of variable var is $var. While the second echo statement will be: The value of variable var is foo.

In PHP, single quoted strings will display the name of a variable while a double quote will display the value of the variable. Just a fun fact that is useful when you want to include a variable in a string you are echoing. You can do either way and it all depends on how you are programming and the style, but either concatenation or embedding a variable using double quotes will give you the same thing. Concatenation is good because it allows you to find the variables that you are adding to a string easily. I use the double quoted way as I trained myself to find variables by the $ and I can find variables with ease inside any PHP script.

I know this is a little bit out of scope of not only this post, but the subject of discussion, however I thought you might find the alternative a little bit interesting.

Cheers!