PHP assignment operation

Assignment operation:=, which means that the value of the expression on the right is assigned to the operand on the left.

$int1=10;
$int1=$int1-6; //$int1=4

echo $int1,"<br>"; 

$int3=$int2=$int1+4;  //右向左,最后$int3=8

echo $int2,"<br>"; 
echo $int3,"<br>"; 



$int3=($int2=$int1)+4;  //先对()进行运算,再右向左,最后$int3=8

echo $int2,"<br>"; 
echo $int3,"<br>";

2. Swap the values ​​of two variables

$int_x=10;
$int_y=20;

$int_x=$int_y+$int_x;
$int_y=$int_x-$int_y;
$int_x=$int_x-$int_y;

echo "<hr>";
echo $int_x,"<br>"; 
echo $int_y,"<br>";

3. Reference assignment

$x=6;$y=$x;$z=&$y; //means $y, $z Two variables point to the same data