[英]Optional type '$T11' cannot be used as a boolean; test for '!= nil' instead since installing XCode 6 beta 7
Here is the code where I'm getting the error: 这是我收到错误的代码:
for (key, value) in info {
let fieldValue: AnyObject? = value
if (!fieldValue || fieldValue?.length == 0) { // this line gives the error
informationComplete = false;
}
}
This is what XCode suggests I use which causes another error: 这就是XCode建议我使用它导致另一个错误:
for (key, value) in info {
let fieldValue: AnyObject? = value
if ((!fieldValue || fieldValue?.length == 0) != nil) { //bool not convertible to string
informationComplete = false;
}
}
Help is appreciated. 感谢帮助。
Thanks for your time 谢谢你的时间
Optionals are no longer considered boolean expression (as stated in the Swift Reference - Revision History ): Optionals不再被视为布尔表达式(如Swift参考 - 修订历史中所述 ):
Optionals no longer implicitly evaluate to true when they have a value and false when they do not, to avoid confusion when working with optional Bool values. Optionals在有值时不再隐式评估为true,而在没有值时则不再为false,以避免在使用可选的Bool值时出现混淆。 Instead, make an explicit check against nil with the == or != operators to find out if an optional contains a value. 相反,使用==或!=运算符对nil进行显式检查,以确定可选项是否包含值。
so you have to make it explicit as follows: 所以你必须明确如下:
if (fieldValue == nil || ...
I remember that changed in beta 6 - were you using beta 5? 我记得在测试版6中有所改变 - 你使用的是beta 5吗?
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