Php: what's the difference between $var and &$var?

Question

What is the difference between

foreach ($my_array as $my_value) {
}

And:

foreach ($my_array as &$my_value) {
}

Answer 1

A real world example for & use is when you need to change the content of an array with very few lines of code

foreach($arrFeed as &$objFeed)
  $objFeed['externalSrc'] = convertToLocalImage($objFeed['externalSrc']);