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限制双精度到两位小数,不带尾随零

nsnumberformatter decimal cocoa-touch objective-c iphone

36

testing · 技术社区 · 15 年前

我读过 this that . 我想要这个:

1.4324=>“1.43”
9.4000=>“9.4”
43.000=>“43”

9.4=>“9.40”(错误)

两个问题的答案都指向 NSNumberFormatter

- (void)viewDidLoad {
    [super viewDidLoad];
    UILabel *myLabel = [[UILabel alloc] initWithFrame:CGRectMake(50, 100, 200, 20)];

    NSNumberFormatter *doubleValueWithMaxTwoDecimalPlaces = [[NSNumberFormatter alloc] init];
    [doubleValueWithMaxTwoDecimalPlaces setNumberStyle:NSNumberFormatterDecimalStyle];
    [doubleValueWithMaxTwoDecimalPlaces setPaddingPosition:NSNumberFormatterPadAfterSuffix];
    [doubleValueWithMaxTwoDecimalPlaces setFormatWidth:2];

    NSNumber *myValue = [NSNumber numberWithDouble:0.01234];
    //NSNumber *myValue = [NSNumber numberWithDouble:0.1];

    myLabel.text = [doubleValueWithMaxTwoDecimalPlaces stringFromNumber:myValue];

    [self.view addSubview:myLabel];
    [myLabel release];
    myLabel = nil;
    [doubleValueWithMaxTwoDecimalPlaces release];
    doubleValueWithMaxTwoDecimalPlaces = nil;
}

我也试过了

NSString *resultString = [NSString stringWithFormat: @"%.2lf", [myValue doubleValue]];
NSLog(@"%@", resultString);

解决方案:

NSNumberFormatter *doubleValueWithMaxTwoDecimalPlaces = [[NSNumberFormatter alloc] init];
[doubleValueWithMaxTwoDecimalPlaces setNumberStyle:NSNumberFormatterDecimalStyle];
[doubleValueWithMaxTwoDecimalPlaces setMaximumFractionDigits:2];
NSNumber *myValue = [NSNumber numberWithDouble:0.01234];
NSLog(@"%@",[doubleValueWithMaxTwoDecimalPlaces stringFromNumber:myValue]];
[doubleValueWithMaxTwoDecimalPlaces release];
doubleValueWithMaxTwoDecimalPlaces = nil;

3 回复 | 直到 9 年前

1

44

Chris Gummer 15 年前

配置格式化程序时,请尝试添加以下行:

    [doubleValueWithMaxTwoDecimalPlaces setMaximumFractionDigits:2];

2

0

PeyloW 15 年前

把字符串末尾不需要的字符剪下来怎么样?:

NSString* CWDoubleToStringWithMax2Decimals(double d) {
    NSString* s = [NSString stringWithFormat:@"%.2f", d];
    NSCharacterSet* cs = [NSCharacterSet characterSetWithCharacterInString:@"0."];
    NSRange r = [s rangeOfCharacterInSet:cs
                                 options:NSBackwardsSearch | NSAnchoredSearch];
    if (r.location != NSNotFound) {
      s = [s substringToIndex:r.location];
    }
    return s;
}

3

0

Nirav Ghori 9 年前

 NSNumberFormatter *numberFormatter = [[NSNumberFormatter alloc] init];
[numberFormatter setNumberStyle:NSNumberFormatterDecimalStyle];
[numberFormatter setRoundingMode:NSNumberFormatterRoundDown];
[numberFormatter setMinimumFractionDigits:2];
numberFormatter.positiveFormat = @"0.##";
NSNumber *num = @(total_Value);