How do i fill an objects attributes dynamically? - php

Question

I am trying to save an object with a variable amount of "cols". The number of cols is equal to the number of headers. This is how the code looked before:
if(isset($_POST['submit'])){
$sub = new Sub();
$sub->product_id = $_POST['product_id'];
$sub->col1 = $_POST['col1'];
$sub->col2 = $_POST['col2'];
$sub->col3 = $_POST['col3'];
$sub->col4 = $_POST['col4'];
$sub->col5 = $_POST['col5'];
$sub->col6 = $_POST['col6'];
$sub->col7 = $_POST['col7'];
$sub->col8 = $_POST['col8'];
$sub->col9 = $_POST['col9'];
$sub->col10 = $_POST['col10'];
$sub->col11 = $_POST['col11'];
$sub->col12 = $_POST['col12'];
$sub->col13 = $_POST['col13'];
$sub->col14 = $_POST['col14'];
$sub->col15 = $_POST['col15'];
This is how I want it to look:
if(isset($_POST['submit'])){
$sub = new Sub();
$sub->product_id = $_POST['product_id'];
$i = 0;
foreach($headers as $header){
$i++ ;
$sub->col.$i = $_POST['col'.$i];
}
How do I pass the variable $i into the object's attributes? $sub->(col.$i) ? $sub->(col{$i}) ? Please help me figure this out =) Thank you

Answer 1

Try this:
$sub = new Sub();
$sub->product_id = $_POST['product_id'];
for($i = 1; $i <= count($headers); ++$i)
$sub->{'col' . $i} = $_POST['col' . $i];
But, this is really not the way that the columns should be stored in the Sub object, you should use an array:
$sub->columns = array();
for($i = 1; $i <= count($headers); ++$i) {
$sub->columns[] = $_POST['col' . $i];
}

Answer 2

You have to use {} :
$sub->{'col' . $i} = ...

Answer 3

$field = "col$i";
$sub->$field = "whatver"

Answer 4

I'd prefer a setter method.
class Sub {
public function set($attribute, $value) {
$this->$attribute = $value;
}
}
Now you can do:
foreach($_POST as $key => $value) {
$sub->set($key, $value)
}
Or without the loose coupling:
$i = 1;
while($value = $_POST['col' . $i]) {
$sub->set('col' . $i, $value);
$i++;
}