PHP array is null after passing to function - php

Question

So I have a problem I have an array that is passes to setData function
after that I call getE that suppose to return the array but instead I'm getting Null what am I doing wrong?
<?php
class Se {
public $data1;
public function setData(array $data){
if (empty($data)) {
throw new InvalidArgumentException('The name of an employee cannot be empty.');
}
$data1 = $data;
$data1 = array_values($data1);
var_dump($data1);
}
public function getE(){
return $data1[0];
}
}
$tmpaaa= array('3333','222');
$ttt = new Se();
$ttt->setData($tmpaaa);
echo $ttt->getE();
So my revised code looks like this now
class Se {
public $data1;
public function setData(array $data)
{
if (empty($data))
{
throw new InvalidArgumentException('The name of an employee cannot be empty.');
}
$this->data1 = $data;
}
public function getE()
{
return $this->$data1[0];
}
};
$tmpaaa= array('3','2');
$ttt = new Se();
$ttt->setData($tmpaaa);
echo $ttt->getE();
?>

Answer 1

In order to access class instance properties from within the class, you need to prefix the variable name with $this. See http://php.net/manual/language.oop5.properties.php
To fix your problem, change this in setData
$data1 = $data;
$data1 = array_values($data1);
var_dump($data1);
to this
$this->data1 = array_values($data);
var_dump($this->data1);
and getE to
public function getE(){
return $this->data1[0];
}
Update
As it appears the $data1 property is required in Se, I'd set it in the constructor, eg
public function __construct(array $data) {
$this->setData($data);
}
and instantiate it with
$ttt = new Se($tmpaaa);
echo $ttt->getE();

Answer 2

It is also recommended not closing the php tag in a class file, this prevents space issues.
<?php
class Se {
public $data1;
public function setData(array $data)
{
if (empty($data))
{
throw new InvalidArgumentException('The name of an employee cannot be empty.');
}
$this->data1 = array_values($data); //you error was here, no need to to assign $data twice so I deleted top line.
}
public function getE()
{
return $this->data1[0];
}
}
$tmpaaa = array('3333','222');
$ttt = new Se();
$ttt->setData($tmpaaa);
echo $ttt->getE();