When putting rows into array it duplicates

I am trying to create a class for easier safe MySQLi connections an queries, but I came across this problem where it duplicates $row like [0] => 47, [example_id] => 47 Basically lets say I got a table like this

╒═══════════════════════════════════════════════╕
│                     Content                   |
╞════════════╤═══════════════╤══════════════════╡
│ example_id │ example_title │ example_content  │
╞════════════╪═══════════════╪══════════════════╡
╞════════════╪═══════════════╪══════════════════╡
│ 1          │ Hello World 1 │ Some content 1   │
╞════════════╪═══════════════╪══════════════════╡
│ 2          │ Hello World 2 │ Some content 2   │
╘════════════╧═══════════════╧══════════════════╛

public function select_all(string $table){ // In this case $table = 'Content'
  $this->remove_stmt();

  $this->num_rows = null;
  $this->rows = Array();

  if(!$stmt = $this->con->prepare("SELECT * FROM $table")){
    $this->stmt_is_errors = true;
    $this->stmt_errors = 'Could not prepare statement!';
    return false;
  }

  if(!$stmt->execute()){
    $this->stmt_is_errors = true;
    $this->stmt_errors = 'Could not execute statement!';
    return false;
  }

  if(!$result = $stmt->get_result()){
    $this->stmt_is_errors = true;
    $this->stmt_errors = 'Could not get result content!';
    return false;
  }

  if(!$this->num_rows = $result->num_rows){
    $this->stmt_is_errors = true;
    $this->stmt_errors = 'Could not get number of rows';
    return false;
  }

  $row = Array();
  while($row = $result->fetch_array()){
    $this->rows[] = $row;
    print_r($row);
    echo '<br><br>';
  }

  return true;

}

Using the code above on the example table you can see on the very top of this post will output an array looking like this:

Array(
    [0] => Array(
        [0] => 1,
        [example_id] => 1,
        [1] => "Hello World 1",
        [example_title] => "Hello World 1",
        [2] => "Some content 1",
        [example_content] => "Some content 2"
    ),
    [1] => Array(
        [0] => 2,
        [example_id] => 2,
        [1] => "Hello World 2",
        [example_title] => "Hello World 2",
        [2] => "Some content 2",
        [example_content] => "Some content 2"
    ),
);

How would I avoid these duplicates?

Thanks. Richard.

You are using $result->fetch_array() and this function, if used without a parameter will use the default parameter which is MYSQLI_BOTH which returns both a numeric array and an assoc array with each fetch

So either use $result->fetch_array(MYSQLI_ASSOC)

or you can use $result->fetch_assoc() which will return just an assoc array