ios - json 解析float类型多出几位小数怎么处理？

Question

后台返回float类型数据8.2，实际用AFN的json解析后得到8.1999999999怎么回事？该怎么处理啊？

Answer 1

Isn’t the returned string a string? id = 2747 is the basic data type. Let the background process it directly

Answer 2

Try using NSNumber accept? Then, sometimes the type conversion does go wrong, and then you can try it again on the browser.

Answer 3

Thank you everyone, I have found a solution. When returning float or double type in the background, use NSDecimalNumber to deal with the problem of precision loss.
Here I received it in string mode and directly added the NSString classification. The correction method is posted as follows:

+(NSString )reviseString:(NSString )string{

/* 直接传入精度丢失有问题的Double类型*/
double conversionValue        = (double)[string floatValue];
NSString *doubleString        = [NSString stringWithFormat:@"%lf", conversionValue];
NSDecimalNumber *decNumber    = [NSDecimalNumber decimalNumberWithString:doubleString];
return [decNumber stringValue];

}

The data returned in this way is the corrected precision data. Because of personal needs, it is converted into string type