轉換階數成的NSNumber

Question

我無法轉換等9.471347923322231e + 18一個階數成一個NSNumber。有誰知道如何做到這一點呢？謝謝。

Answer 1

對於指數號碼，你應該使用：

NSDecimalNumber *number = [NSDecimalNumber decimalNumberWithMantissa:12345 
             exponent:-3 
             isNegative:YES]; 

，或者如果你想從NSString的得到它：

+ (NSDecimalNumber *)decimalNumberWithString:(NSString *)numericString locale:(NSDictionary *)locale; 

例如：

NSString *stringNumber = @"9.471347923322231e+18"; 
NSDictionary *locale = [NSDictionary dictionaryWithObject:@"." forKey:NSLocaleDecimalSeparator]; 
NSDecimalNumber *number = [NSDecimalNumber decimalNumberWithString:stringNumber locale:locale];