Question

我正在尝试格式化一些float，如下所示：

1.1500将显示为“$ 1.15”
1.1000将显示为“$ 1.10”
1.0000将显示为“$ 1.00”
1.4710将显示为“$ 1.471”
1.4711将显示为“$ 1.4711”

我试过

NSString *answer = [NSString stringWithFormat:@"$ %.2f",myvalue];

Answer 1

这正是NSNumberFormatters的用途：

float onefifteen = 1.1500;    // displayed as “$ 1.15”
float oneten = 1.1000;     // displayed as “$ 1.10”
float one = 1.0000;    // displayed as “$ 1.00”
float onefortyseventen = 1.4710;    // displayed as “$ 1.471”
float onefortyseveneleven = 1.4711;    // displayed as “$ 1.4711”

NSNumberFormatter * formatter =  [[NSNumberFormatter alloc] init];
[formatter setNumberStyle:NSNumberFormatterCurrencyStyle];
[formatter setUsesSignificantDigits:YES];   
// The whole number counts as the first "significant digit"
[formatter setMinimumSignificantDigits:3]; 

NSLog(@"%@", [formatter stringFromNumber:[NSNumber numberWithFloat:onefifteen]]);
NSLog(@"%@", [formatter stringFromNumber:[NSNumber numberWithFloat:oneten]]);
NSLog(@"%@", [formatter stringFromNumber:[NSNumber numberWithFloat:one]]);
NSLog(@"%@", [formatter stringFromNumber:[NSNumber numberWithFloat:onefortyseventen]]);
NSLog(@"%@", [formatter stringFromNumber:[NSNumber numberWithFloat:onefortyseveneleven]]);

2011-12-15 19：36：52.185重要事项[49282：903] $ 1.15
  2011-12-15 19：36：52.190重要事项[49282：903] $ 1.10
  2011-12-15 19：36：52.190重要事项[49282：903] $ 1.00
  2011-12-15 19：36：52.191重要事项[49282：903] $ 1.471
  2011-12-15 19：36：52.192重要事项[49282：903] $ 1.4711

Answer 2

试试这个：

   NSString *answer = [NSString stringWithFormat:@"%.02f", myvalue];

Answer 3

我已经弄明白了。您可以按照以下实施方式执行此操作。

请看下面的演示代码......

NSArray * numbers = [[NSArray alloc] initWithObjects:@"1.1500",@"1.1000",@"1.0000",@"1.4710",@"1.4711",nil];

for (int i=0; i<[numbers count]; i++) {
    NSArray * floatingPoint = [[numbers objectAtIndex:i] componentsSeparatedByString:@"."];
    NSString * lastObject = [[floatingPoint lastObject] stringByReplacingOccurrencesOfString:@"0" withString:@""];
    if ([lastObject length] < 2) {
        NSLog(@"%@",[NSString stringWithFormat:@"$ %.2f",[[numbers objectAtIndex:i] floatValue]]);
    } else {
        NSLog(@"%@",[NSString stringWithFormat:@"$ %g",[[numbers objectAtIndex:i] floatValue]]);
    }
}

谢谢，

MinuMaster

Answer 4

阅读format specifiers.

上的文档

将浮点数格式化为NSString时，会截断额外的零

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