遇到一个问题 服务器返回货币数据 妈的 用string 》 floatvalue 不准确
NSDecimalNumberHandler *roundUp = [NSDecimalNumberHandler
decimalNumberHandlerWithRoundingMode:NSRoundBankers
scale:2
raiseOnExactness:NO
raiseOnOverflow:NO
raiseOnUnderflow:NO
raiseOnDivideByZero:YES];
枚举
NSRoundPlain, // Round up on a tie ／／貌似取整 翻译出来是个圆 吗的垃圾百度翻译
NSRoundDown, // Always down == truncate ／／只舍不入
NSRoundUp, // Always up ／／ 只入不舍
NSRoundBankers // on a tie round so last digit is even 貌似四舍五入
//90.7049+0.22 然后四舍五入
NSDecimalNumber *subtotal = [NSDecimalNumber decimalNumberWithString:@"90.7049"];
NSDecimalNumber *discount = [NSDecimalNumber decimalNumberWithString:@"0.22"];
NSDecimalNumber *total = [subtotal decimalNumberByAdding:discount withBehavior:roundUp];
NSLog(@"Rounded total: %@", total);
NSDecimalNumber 其他用法
所有NSDecimalNumber对象是不可变的，这意味着已经被创建后不能改变它们的值。
NSDecimalNumber*price;
price = [NSDecimalNumber decimalNumberWithMantissa:1599
exponent:-2 ／／10的－2次方
isNegative:NO];
等效
price = [NSDecimalNumber decimalNumberWithString:@"15.99"];
NSDecimalNumber*price1 = [NSDecimalNumber decimalNumberWithString:@"15.99"];
NSDecimalNumber*price2 = [NSDecimalNumber decimalNumberWithString:@"29.99"];
NSDecimalNumber*coupon = [NSDecimalNumber decimalNumberWithString:@"5.00"];
NSDecimalNumber*discount = [NSDecimalNumber decimalNumberWithString:@".90"];
NSDecimalNumber*numProducts = [NSDecimalNumber decimalNumberWithString:@"2.0"];
NSDecimalNumber *subtotal = [price1 decimalNumberByAdding:price2];
NSDecimalNumber *afterCoupon = [subtotal decimalNumberBySubtracting:coupon];
NSDecimalNumber *afterDiscount = [afterCoupon decimalNumberByMultiplyingBy:discount];
NSDecimalNumber *average = [afterDiscount decimalNumberByDividingBy:numProducts];
NSDecimalNumber*averageSquared = [average decimalNumberByRaisingToPower:2];
subtotal的NSLog（@“小计：％@”，price1加price2后）;/ / 45.98
afterCoupon的NSLog（@“subtotal优惠券后：％@”，subtotal减coupon）;/ / 40.98
afterDiscount的NSLog（（@“折后：％@”），9/10）;/ / 36.882
average的NSLog（@“每股平均价产品：％@”，平均）;/ / 18.441
averageSquared的NSLog（@“平均价的平方：％@”，averageSquared）;/ / 340.070481
//保留小数点后两位
NSDecimalNumberHandler*roundUp = [NSDecimalNumberHandler
decimalNumberHandlerWithRoundingMode:NSRoundUp
scale:2
raiseOnExactness:NO
raiseOnOverflow:NO
raiseOnUnderflow:NO
raiseOnDivideByZero:YES];
//9折后 36.882 有余进位结果 36.89
NSDecimalNumber*subtotal = [NSDecimalNumber decimalNumberWithString:@"40.98"];
NSDecimalNumber*discount = [NSDecimalNumber decimalNumberWithString:@".90"];
NSDecimalNumber*total = [subtotal decimalNumberByMultiplyingBy:discount
withBehavior:roundUp];
NSLog(@"Rounded total: %@", total);
//比较大小
NSDecimalNumber*discount1 = [NSDecimalNumber decimalNumberWithString:@".85"];
NSDecimalNumber*discount2 = [NSDecimalNumber decimalNumberWithString:@".9"];
NSComparisonResult result = [discount1 compare:discount2];
if (result ==NSOrderedAscending) {
NSLog(@"85%% < 90%%小于");
} else if (result == NSOrderedSame) {
NSLog(@"85%% == 90%%等于");
} elseif (result ==NSOrderedDescending) {
NSLog(@"85%% > 90%%大于");
}
以上只是简单的使用介绍不足之处请大家指正，共同学习进步，谢谢。
