php operators and variables

[Guest Cashster09]

I am going thru some tutorials and came across this and wondered why? I am a beginner with this stuff...thanks in advance

 

on the echo statements they are surrounded by "". HOw come the variables are surrounded by quotes and a period?

 

Why not just "Perform addition: 2 + 4 = $addition";

 

$addition = 2 + 4;

$subtraction = 6 - 2;

$multiplication = 5 * 3;

$division = 15 / 3;

$modulus = 5 % 2;

echo "Perform addition: 2 + 4 = ".$addition."<br />";

echo "Perform subtraction: 6 - 2 = ".$subtraction."

";

echo "Perform multiplication: 5 * 3 = ".$multiplication."

";

echo "Perform division: 15 / 3 = ".$division."

";

echo "Perform modulus: 5 % 2 = " . $modulus

. ". Modulus is the remainder after the division operation has been performed.

In this case it was 5 / 2, which has a remainder of 1.";

 

thanks in advance,

Rich

[jlhaslip]

The period is a concatenation operator. It separates different parts of the string to be echo'd out.

 

echo "This part " . $this_variable . " and another part. 
";

 

Notice also that the same output can be done using single quotes:

 

echo 'This part ' . $this_variable . ' and another part. 
';

 

Or Double quotes as you suggest:

 

echo "This part  $this_variable  and another part. 
";

 

Test script:

$this_variable = "This Variable";
echo "This part " . $this_variable . " and another part. 
";
echo 'This part ' . $this_variable . ' and another part. 
';
echo "This part  $this_variable  and another part. 
";
?>

The biggest difference is that the single quote stuff does not get 'parsed' and it will be faster on the Server. Not a big deal on a small script, but it can bog down on a larger script.

[Guest Cashster09]

Ok, now i see!

I was looking at all the quotes differently....it looked like there were quotes around the variables....

 

It really is

echo "Perform addition: 2 + 4 = " .$addition. "

";

 

So the concatenation can have spaces or not?

echo "Perform addition: 2 + 4 = " . $addition . "

"; Which is easier to read and decipher than the one below

echo "Perform addition: 2 + 4 = ".$addition."

";

 

both these are correct, then?

Edited May 22, 2009 by Cashster09

[jlhaslip]

Correct. I 'space them out' so they are easier to read. Personal choice.

[Guest Cashster09]

Cool!...

 

Now i can sleep at nite knowing that i understand something about php....