在处理金额计算时,往往会涉及到小数,由于Double类型不准确,无法做到产品的要求。为了保证金额计算的准确性,建议使用NSDecimalNumber。
1.创建对象(常用的方法)
// mantissa:长整型数值;exponent:指数(几次方);flag:正负数。 + (NSDecimalNumber *)decimalNumberWithMantissa:(unsigned long long)mantissa exponent:(short)exponent isNegative:(BOOL)flag; NSDecimalNumber *decimalNumber = [NSDecimalNumber decimalNumberWithMantissa:829 exponent:-2 isNegative:NO]; //8.29 decimalNumber = [NSDecimalNumber decimalNumberWithMantissa:829 exponent:2 isNegative:YES]; //-82900 // locale代表一种格式 + (NSDecimalNumber *)decimalNumberWithString:(nullable NSString *)numberValue locale:(nullable id)locale; NSDictionary *locale = [NSDictionary dictionaryWithObject:@"," forKey:NSLocaleDecimalSeparator]; //以","当做小数点格式 NSDecimalNumber *discountAmount = [NSDecimalNumber decimalNumberWithString:@"123,40" locale:locale]; //123.4 + (NSDecimalNumber *)decimalNumberWithString:(nullable NSString *)numberValue;
2.逻辑运算
加: - (NSDecimalNumber *)decimalNumberByAdding:(NSDecimalNumber *)decimalNumber; - (NSDecimalNumber *)decimalNumberByAdding:(NSDecimalNumber *)decimalNumber withBehavior:(nullable id <NSDecimalNumberBehaviors>)behavior; 减: - (NSDecimalNumber *)decimalNumberBySubtracting:(NSDecimalNumber *)decimalNumber; - (NSDecimalNumber *)decimalNumberBySubtracting:(NSDecimalNumber *)decimalNumber withBehavior:(nullable id <NSDecimalNumberBehaviors>)behavior; 乘: - (NSDecimalNumber *)decimalNumberByMultiplyingBy:(NSDecimalNumber *)decimalNumber; - (NSDecimalNumber *)decimalNumberByMultiplyingBy:(NSDecimalNumber *)decimalNumber withBehavior:(nullable id <NSDecimalNumberBehaviors>)behavior; 除: - (NSDecimalNumber *)decimalNumberByDividingBy:(NSDecimalNumber *)decimalNumber; - (NSDecimalNumber *)decimalNumberByDividingBy:(NSDecimalNumber *)decimalNumber withBehavior:(nullable id <NSDecimalNumberBehaviors>)behavior; a的n次方: - (NSDecimalNumber *)decimalNumberByRaisingToPower:(NSUInteger)power; - (NSDecimalNumber *)decimalNumberByRaisingToPower:(NSUInteger)power withBehavior:(nullable id <NSDecimalNumberBehaviors>)behavior; 指数运算: - (NSDecimalNumber *)decimalNumberByMultiplyingByPowerOf10:(short)power; - (NSDecimalNumber *)decimalNumberByMultiplyingByPowerOf10:(short)power withBehavior:(nullable id <NSDecimalNumberBehaviors>)behavior; 四舍五入运算: - (NSDecimalNumber *)decimalNumberByRoundingAccordingToBehavior:(nullable id <NSDecimalNumberBehaviors>)behavior; 比较运算: -(NSComparisonResult)compare:(NSNumber *)decimalNumber;
3.数值格式设置
// roundingMode:舍入模式; scale:保留几位小数;exact:发生精确错误时是否抛出异常,一般为NO;overflow:发生溢出错误时是否抛出异常,一般为NO; underflow:发生不足错误时是否抛出异常,一般为NO; divideByZero:被0除时是否抛出异常,一般为YES + (instancetype)decimalNumberHandlerWithRoundingMode:(NSRoundingMode)roundingMode scale:(short)scale raiseOnExactness:(BOOL)exact raiseOnOverflow:(BOOL)overflow raiseOnUnderflow:(BOOL)underflow raiseOnDivideByZero:(BOOL)divideByZero; NSDecimalNumberHandler *roundUp = [NSDecimalNumberHandler decimalNumberHandlerWithRoundingMode:NSRoundDown scale:2 raiseOnExactness:NO raiseOnOverflow:NO raiseOnUnderflow:NO raiseOnDivideByZero:YES];
时间: 2024-10-20 23:07:37