Question

I have the following code

$arr =  array(
     'media[]'  => "@{$image};type=image/jpeg;filename={$image}"
);

I do not know what line 2 means.
What do the [], @ and {} stand for?

UPDATE:

This is a code extracted from Upload images on Twitter using PHP.

Used to upload images to Twitter. I need to implement the same in Lua. Hence this question.

Answer 1

$arr =  array(
     'media[]'  => "@{$image};type=image/jpeg;filename={$image}",
);

is just like

$arr =  array(
     'media[]'  => "@".$image.";type=image/jpeg;filename=".$image,
);

See the PHP manual for what the curly brackets ({}) mean in double-quoted strings.

And for "[]" and "@" they are just normal strings.