Confused about Pset7 Distro Code

Question

Currently working through pset7 (Finance) and can't seem to wrap my head around how this piece of code works:

$positions = [];
//iterate through rows
foreach ($rows as $row)
{
    $stock = lookup($row["symbol"]);
    if ($stock !== false)
    {
        $positions[] = [
            "name" => $stock["name"],
            "price" => $stock["price"],
            "shares" => $row["shares"],
            "symbol" => $row["symbol"]
        ];
    }
}

Through every iteration through rows, wouldn't $positions["shares"] and $positions["symbol"] get over written by the new values from $row["shares"] and $row["symbol"]? How is $positions able to store all the rows of $rows?

Answer 1

Each $row[] is stored as an associative array. $positions[] is an array of arrays. The values in each row do not overlap, because they are stored in adjacent arrays.

EDIT:

The code does iterate through $positions, in a way. More precisely, the code iterates through the $rows returned by the database query using foreach ($rows as $row).

For each row, it passes the value of $row["symbol"] as an argument to the lookup() function and returns the associative array $stock.

Then it uses some values from $row and some values from $stock to create a new indexed array called $positions, which it builds up row by row (or position by position).

These keys and values will be needed later in order to pass data to render(portfolio.php). Get it?

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