Calculation error with Numbers containing more than 3 Digits - php

Question

I'm importing prices from a database using the following code:
//implode items, turn into string
$item_implode = join("','", $item_array);
//declare an overall array for result
$product = array();
$result = $mysqli->query("SELECT Name, WPrice as price, APrice as a_price from my_table where Name IN ('$item_implode') ORDER BY FIELD (Name, '$item_implode');");
while($row = $result->fetch_assoc()) {
$product_name = $row['Name'];
// find all keys in $item_array which value is the products
$keys = array_keys($item_array, $product_name);
foreach ($keys as $key) {
// add values for these keys
$product[$key + 1]["Name"] = $row['Name'];
$product[$key + 1]["price"] = number_format($row['price'],2);
$product[$key + 1]["a_price"] = number_format($row['a_price'],2);
}
}
And then I apply the following functions:
function price($m) {
global $product,$i;
if ($m == "a") {
$value = $product[$i]["a_price"];
}
else {
$value = $product[$i]["price"]; //
}
return $value;
}
I'm trying to use the following comparison:
<?php if ( price( a )< price( default ) ) {echo "Smaller";} ?>
To echo Smaller whenever the price of A is smaller than the default price.
It works fine for prices in the range of 0 to 999.99, but for when a price of 1,000 or more is involved, I'm getting the opposite results (it echos smaller when bigger and vice-versa)
What is causing this problem?

Answer 1

You're comparing strings because that's what you stored in $product["price"] and $product["a_price"] (the function number_format() returns a string value). For numbers >= 1000, those strings include commas, which breaks the comparison.
Compare the numeric values and don't call number_format() until you need to display the values.