在Swift数组中找到元素的总和(Finding sum of elements in Swift array)

 是： 
 
$boolean = !$boolean;
 
 如果它不是一个布尔值，你可以使用三元结构： 
 
$int = ($some_condition ? 1 : 2); // if $some_condition is true, set 1
                                  // otherwise set 2

Yes:
 
$boolean = !$boolean;
 
if it's not a boolean value, you can use the ternary construction:
 
$int = ($some_condition ? 1 : 2); // if $some_condition is true, set 1
                                  // otherwise set 2