[Explain:"$fieldname = $_REQUEST['fieldname']"]

NEWBIE ALERT:

New to Programming

Newer to PHP

Bad at formulating coherent questions.....so here it goes....

 

Could someone explain

$fieldname = $_REQUEST['fieldname']

 

I understand "$_REQUEST An associative array that by default contains the contents of $_GET, $_POST and $_COOKIE"

 

I also understand you call the member of an array like so: 

<?php
$arr = array("foo" => "bar", 12 => true);

echo $arr["foo"]; // bar
echo $arr[12];    // 1
?>

 

So I would expect that if someone wants to use something from the $_REQUEST Array they would use:

$fieldname = $_REQUEST['$_GET']

So I do not understand why "$fieldname" is inside the brackets.I suspect they might be setting this up to use $fieldname instead of $_REQUEST maybe...but why, that would be redundant? so I suspect I suspect wrong....

[Use of %]

Wow, I just learned something really cool about PHP..thanks for the answer and for providing the helpful links!!!!!

[Use of %]

What does the % sign men in this context

'before_widget' => '<li id="%1$s" class="widget-container %2$s">',