variable scope in php function - php

Question

Here is my script.
I declared few variable outside function. I want to use it in function, would it be available?
<?php
session_start();
require_once('twitteroauth/twitteroauth.php');
require_once('follow.php');
require_once('config.php');
if (empty($_SESSION['access_token']) || empty($_SESSION['access_token']['oauth_token']) || empty($_SESSION['access_token']['oauth_token_secret'])) {
header('Location: ./clearsessions.php');
}
$access_token = $_SESSION['access_token'];
$connection = new TwitterOAuth(CONSUMER_KEY, CONSUMER_SECRET, $access_token['oauth_token'], $access_token['oauth_token_secret']);
$content = $connection->get('account/verify_credentials');
$twitteruser = $content->{'screen_name'};
$userid = $content->{'id'};
$temp = "1";
$tweets1 = $connection->get("https://api.twitter.com/1.1/statuses/retweets_of_me.json?count=200");
$tweets3 = $connection->get("https://api.twitter.com/1.1/statuses/user_timeline.json?trim_user=true&include_rts=true");
$tweets4 = $connection->get("https://api.twitter.com/1.1/statuses/home_timeline.json?include_rts=true&trim_use=true");
foreach ($tweets1 as $item)
{
$text = $item->text;
$follow_count = getfollow($m[1]);
echo "followe count is $follow_count <br>";
lookup($item->user->id_str);
}
function lookup($userid)
{
//echo "userid : $userid temp : $temp";
$tweets5 = $connection->get("https://api.twitter.com/1.1/users/lookup.json?user_id='.$userid.' ");
$CONNECTION IS not availabl here? WHY?
foreach ($tweets5 as $item)
{
$text = $item->name;
}
return;
}
?>

Answer 1

A function has its own scope. You have to provide all variables you want to use in arguments except if they are in the $_SESSION, $_SERVER etc. variables.

Answer 2

Hand it over via parameter:
function lookup($userid, $connection) {
//code here
}
Only Superglobals are availible inside functions. Everything else is handed over via parameters.

Answer 3

You can use outside variable by defining them as global or you can pass them to functions as a parameters.
$str= 'str';
function test()
{
global $str;
echo $str;
}
or
function test($str)
{
echo $str;
}

Answer 4

using the global keyword should do the trick:
$foo = '123';
function bar() {
global $foo;
echo $foo;
}
but the way I see it, you could just pass the variable to that function instead.