如何在此if语句中添加“OR”运算符？

Question

我有这个IF语句，我想添加一个OR，所以它应该是如果（$变量1 == $变量2）或如果（$变量3 == $变量4）。

if($variable1 == $variable2) 
die(""); 

else 
echo(""); 

Answer 1

见PHP Logical Operators

if($variable1 ==$variable2 || $variable3 == $variable4) { 
//do whatever 
} 

Answer 2

if($variable1 == $variable2 || $variable3 == $variable4){ 
die(""); 
} 
else{ 
echo("");} 

Answer 3

if($variable1 == $variable2 || $variable3 == $variable4) 
die(""); 
else 
echo("");