如何使用Swift在一行中分配多个变量？
var blah = 0
var blah2 = 2
blah = blah2 = 3 // Doesn't work???
你不是。这是一个语言功能，用于防止分配的标准不需要的副作用返回一个值，如
described in the Swift book：
原文链接：https://www.f2er.com/swift/320799.htmlUnlike the assignment operator in C and Objective-C,the assignment operator in Swift does not itself return a value. The following statement is not valid:
06000
This feature prevents the assignment operator (
=) from being used by accident when the equal to operator (==) is actually intended. By making ifx = yinvalid,Swift helps you to avoid these kinds of errors in your code.
所以，这有助于防止这种极其常见的错误。虽然这种错误可以在其他语言中减轻 – 例如，通过使用Yoda conditions – Swift设计师显然决定在语言层面确定你不能在脚下射击自己。但它的确意味着你不能使用：
blah = blah2 = 3
如果你绝望在一行上完成赋值，你可以使用元组语法，但你仍然必须指定每个值：
(blah,blah2) = (3,3)
…我不会推荐它。虽然一开始可能会感到不方便，但在我看来，输入整个内容是最好的方式。
blah = 3 blah2 = 3
