xcode 快速将任何对象转换为布尔值？
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Convert any object to boolean in swift?
提问by TechChain
I am getting a dictionary as JSON response from server.From that dictionary there is a key "error"now i want to get the value of "error" key.I know that error always will be either 0or 1.So i tried to get it as boolean but it did not work for me.Please suggest how can i convert its value to boolean.
我正在从服务器获取一个字典作为 JSON 响应。从那个字典有一个键“错误”，现在我想获得“错误”键的值。我知道错误总是0或1。所以我试图将其作为布尔值，但它对我不起作用。请建议我如何将其值转换为布尔值。
let error=jsonResult.objectForKey("error")
//this does not work for me
if(!error)
{
//proceed ahead
}
回答by PGDev
Booldoes not contain an initializer that can convert Intto Bool. So, to convert Intinto Bool, you can create an extension, i.e.
Bool不包含可以转换Int为Bool. 因此，要转换Int为Bool，您可以创建一个extension，即
extension Bool
{
init(_ intValue: Int)
{
switch intValue
{
case 0:
self.init(false)
default:
self.init(true)
}
}
}
Now you can get the value of key error using:
现在您可以使用以下方法获取键错误的值：
if let error = jsonResult["error"] as? Int, Bool(error)
{
// error is true
}
else
{
// error does not exist/ false.
}
回答by pdubal
Updated
更新
Considering jsonResult as NSDictionaryand error value is Bool. you can check it by following way.
将 jsonResult 视为NSDictionary，错误值为Bool. 您可以通过以下方式进行检查。
guard let error = jsonResult.object(forKey: "error") as? Bool else{
// error key does not exist / as boolean
return
}
if !error {
// not error
}
else {
// error
}
回答by Ganpat
Very Simple Way:
很简单的方法：
Create a function:
创建一个函数：
func getBoolFromAny(paramAny: Any)->Bool {
let str = "\(paramAny)"
return str == "1"
}
Use the function:
使用函数：
if let anyData = jsonResult["error"] {
if getBoolFromAny(anyData) {
// error is true
} else {
// error is false
}
}
Also, if you want one line condition, then above function can be reduced like:
另外，如果你想要一个行条件，那么上面的函数可以减少如下：
if let anyData = jsonResult["error"], getBoolFromAny(anyData) {
// error is true
} else {
// error is false
}
回答by gnasher729
Your error is neither 0 or 1. It is an optional object. It is nil if there was no key "error" in your JSON, otherwise it's probably an NSNumber.
您的错误既不是 0 也不是 1。它是一个可选对象。如果您的 JSON 中没有关键的“错误”，则它为零，否则它可能是一个 NSNumber。
It is most likely that nil means "no error" and if it's not nil and contains a zero it means "no error" and if it's not nil and contains a one it means "error" and if it's not nil and contains anything else then something is badly wrong with your json.
很可能 nil 表示“没有错误”，如果它不是 nil 并且包含零，则表示“没有错误”；如果它不是 nil 并且包含一个 1，则表示“错误”，如果它不是 nil 并且包含其他任何内容，则你的 json 有问题。
Try this:
尝试这个：
let errorObject = jsonResult ["error"]
if errorObject == nil or errorObject as? NSInteger == 0
When I say "try", I mean "try". You're the responsible developer here. Check if it works as wanted with a dictionary containing no error, with a dictionary containing an error 0 or 1, and a dictionary containing for example error = "This is bad".
当我说“尝试”时，我的意思是“尝试”。您是这里的负责开发人员。使用不含错误的字典、包含错误 0 或 1 的字典以及包含例如 error = "This is bad" 的字典检查它是否按需要工作。
回答by TechChain
Below code worked for me
下面的代码对我有用
if let error = jsonResult["error"] as? Int where Bool(error)
{
// error is true
print("error is true")
}
else
{
// error does not exist/ false.
print("error is false")
}
回答by Gurdeep
Another Important point here is, you're using Swift and parsing the repsonse as NSDictionary. I can say that because you're using objectForKeymethod. Best practice would be to parse it as Swift Dictionary.
这里的另一个重点是，您正在使用 Swift 并将响应解析为 NSDictionary。我可以这么说是因为你在使用objectForKey方法。最佳实践是将其解析为 Swift Dictionary。
It may look like Dictionary<String:AnyObject>or [String:AnyObject]
它可能看起来像Dictionary<String:AnyObject>或[String:AnyObject]
Then you can check for the error as :
然后你可以检查错误：
if let error = jsonResult["error"] where error == 0 {
//your code
}
回答by Tim Vermeulen
Check equality between errorand 0instead:
检查error和之间的相等性0：
let error = jsonResult.objectForKey("error")
if error == 0 {
// proceed
}
