ios – 无法在JSON解析中将NSNumber桥接到Float

得到此错误：

Fatal error: Unable to bridge NSNumber to Float. What is the problem?

这是原始消息,它是float而不是string.

{\"name\":\"Tomas\",\"gender\":\"male\",\"probability\":0.99,\"count\":594}

解决方法

Swift / Foundation中有许多不同类型的数字.您的NSkeyvalueCoding已设置为NSNumber的实例(请参阅下面的JSON序列化文档的摘录),因此您需要按原样读取,然后根据需要要求将此NSNumber转换为Float：

if let n = d.value(forKey: "probability") as? NSNumber {
    let f = n.floatValue
}

JSONSerialization文档说：

A Foundation object that may be converted to JSON must have the
following properties:

• The top level object is an NSArray or
  NSDictionary.
• All objects are instances of Nsstring,NSNumber,
  NSArray,NSDictionary,or NSNull.
• All dictionary keys are instances of Nsstring.
• Numbers are not NaN or infinity.