从 NSDecimalNumber 中删除负号 (-) 给我一个错误

Question

我有一个 array 里面有 NSDecimalNumbers。我将检查该数字是否为负数。如果是，我想删除负号 (-)。这是我的代码：

NSString *amount = [myArray objectAtInde:2]; // Is a NSDecimalNumber with value of: -397.67

    if ([amount doubleValue] < 0) {
        amount = [amount stringByReplacingOccurrencesOfString:@"-" withString:@"- $"];
    }

当我这样做时，出现以下错误：

Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: '-[NSDecimalNumber stringByReplacingOccurrencesOfString:withString:]: unrecognized selector sent to instance 0x7fcaf94eff80'

Answer 1

请加行，

if ([amount doubleValue] < 0) {
    amount=[NSString stringWithFormat:@"%@",[myArray objectAtIndex:2]];//add line
    amount = [amount stringByReplacingOccurrencesOfString:@"-" withString:@""];
}

它可能适合你，

Answer 2

我刚刚使用了您的代码，它在我这边运行良好。

试过下面的东西，

NSString *amount = @"-397.67";//[myArray objectAtInde:2]; // Is a NSDecimalNumber with value of: -397.67

    if ([amount doubleValue] < 0) {
        amount = [amount stringByReplacingOccurrencesOfString:@"-" withString:@""];
    }

最后试试吧。

如果没有任何效果，则将负浮点值乘以 -1 & 你将得到正数。如果这是你的要求。

Answer 3

你的 [myArray objectAtInde:2] 是 NSDecimalNumber 而不是 NSString，试试这个：

NSDecimalNumber *amountNumber = [myArray objectAtInde:2];
NSString *amount = [NSString stringWithFormat:@"%@", amountNumber];

Answer 4

在您的源文件中添加以下方法

    // multiplies number with -1 if it is less than zero else returns the same 
    - (NSDecimalNumber *)abs:(NSDecimalNumber *)num 
    {
        if ([num compare:[NSDecimalNumber zero]] == NSOrderedAscending) 
        {
            // Number is negative. Multiply by -1
            NSDecimalNumber * negativeOne = [NSDecimalNumber decimalNumberWithMantissa:1
                                                                              exponent:0
                                                                            isNegative:YES];
            return [num decimalNumberByMultiplyingBy:negativeOne];
        } 
        else 
        {
            return num;
        }
    }

并在不进行任何类型转换的情况下将 NSDecimalNumbers 的实例转换为 abs 值，如-

NSDecimalNumbers *number = [myArray objectAtInde:2];

number = [number abs:number];

返回的 number 将包含 NSDecimalNumbers 格式的 abs 值。

Answer 5

如果你的目的是从负值中拯救，那么只需将值转换为绝对值即可。

NSString *amount = [myArray objectAtIndex:2]; // Is a NSDecimalNumber with value of: -397.67

NSLog(@"The value is : %@",[NSString stringWithFormat:@"%.2f", fabs([amount doubleValue])]);

值为：397.67

Answer 6

也许你应该试试这个：

NSString *amount = @(ABS([myArray[2] doubleValue])).stringValue ; // Is a NSDecimalNumber with value of: -397.67

Answer 7

试试这个，

NSDecimalNumber *amountNumber = [myArray objectAtIndex:2]; // Is a NSDecimalNumber with value of: -397.67

NSString *stringWithDollarSymbol = [self addDollarSymoblForNumber:amountNumber];

您可以将 stringWithDollarSymbol 分配给标签

- (NSString *)addDollarSymoblForNumber:(NSDecimalNumber *)decimalNum
{
    NSString *modifiedString = @"";
    if (decimalNum) {
        NSString *numberInStringForm = [decimalNum stringValue];
            if ([decimalNum doubleValue] < 0) { //adds dollor symbol for negative numbers
            modifiedString = [numberInStringForm stringByReplacingOccurrencesOfString:@"-" withString:@"- $"];
        }
        else //adds dollor symbol for positive numbers
        {
            modifiedString = [NSString stringWithFormat:@"$ %@",modifiedString];
        }
    }
    return modifiedString;
}

编辑

使用 NSNumberFormatter 的更好方法：

- (NSString *)formatNumberBasedOnCurrentLocale:(NSDecimalNumber *)number
{
    NSNumberFormatter *formatter = [[NSNumberFormatter  alloc] init];
    [formatter setLocale:[NSLocale currentLocale]];
    [formatter setNumberStyle:NSNumberFormatterCurrencyStyle];
    NSString *result = [formatter stringFromNumber:number];
    if (result.length >0) {
        return result;
    }
    return nil;
}

从 NSDecimalNumber 中删除负号 (-) 给我一个错误

Remove negative symbol (-) from NSDecimalNumber gives me an error

ios

objective-c

nsdecimalnumber