Array in php vs R (pset7 sell.php)

Question

Ok, I'm at pset7 (C$50 Finance), more specifically trying to implement sell.php. I have created a template, sell_form.php, where users can select the symbol of the stock they want to sell and submitted. This symbol is posted to the controller sell.php, and it can be accessed at $_POST["symbol"]. Now what I want to do is to create a variable called $price where i can store the price of the given stock. I want to access the price that is present in the array "positions":

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

is there a way to access only the price of the symbol? If I do the following:

$price = positions[]["price"];

I'm pretty sure I'll get the prices of all the stocks owned by the user. In R accessing data it's pretty easy. All I would have to do is something like

price = positions$price[, symbol == "StockForSale"]

(Actually I'm a little bit rusty with R, so it's possible there is some syntax error, but you get the idea) Is there anything similar in php?

Answer 1

Just like _POST your positions is an associative array. Just as you get $_POST["symbol"] you get $positions["price"].

If I understood correctly you want to do something like the following

<?php

    $values = [
        "name" => "GOOG",
        "price" => 3.5
    ];

    printf("Name: %s\nPrice: %f\n", $values["name"], $values["price"]);

?>

Output

Name: GOOG
Price: 3.500000

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Answer 2

Ok guys, I don't think there is a straightforward way to accomplish what I wanted to do. Instead, I think the best method is to use a for each loop. With the following code I was able to access the price for the symbol that was submitted in $_POST["symbol"] and store it in the variable $price:

$price = 0;
foreach($positions as $position)
{
   if ($position["symbol"] == $_POST["symbol"])
   {
       $price = $position["price"];
   }
}

Hope that will help someone