Strings can look like 0 to the == operator and you can get into uncalled for hithces if you swap the string and numeric operators:

$apples = "apples";
$oranges = "oranges";
if($apples == $oranges){
           print "$apples and $oranges are the same";
           }else {
                 print "$apples and $oranges are not the same";
                 }
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