NSNumberFormatter领先0和小数 [英] NSNumberFormatter leading 0's and decimals

问题描述

有没有办法用前导0和小数格式化NSNumber？例如，我需要能够写入4.5和000.目前我有它允许小数，但不是0的前导。

Is there any way to format an NSNumber with leading 0's and decimals? For example, I need to have the ability to write 4.5 as well as 000. Currently I have it where it will allow decimals, but not leading 0's.

NSNumberFormatter *f = [[NSNumberFormatter alloc] init];
f.numberStyle = NSNumberFormatterNoStyle;

NSString *myString = [f numberFromString:@"4.5"];
NSLog(@"myString: %@",myString);

NSString *myOtherString = [f numberFromString:@"000"];
NSLog(@"myOtherString:%@",myOtherString);

上面的输出是：'myString：4.5'和'myOtherString：0'。我需要能够同时输出'4.5'和'000'作为输出。

The output from above would be: 'myString:4.5' and 'myOtherString:0'. I need to be able to do both '4.5' and '000' as output.

我看过Apple的数据格式指南并没有取得多大成功。

I have looked at Apple's "Data Formatting Guide" without much success.

推荐答案

请注意 [f numberFromString：@4.5] 返回 NSNumber * 不是 NSString *

你想要这样的东西：

NSNumberFormatter *f = [[NSNumberFormatter alloc] init];
f.numberStyle = NSNumberFormatterNoStyle;

NSNumber *myNumber;
NSString *myString;

myNumber = [f numberFromString:@"4.5"];
[f setNumberStyle:kCFNumberFormatterDecimalStyle];
myString = [f stringFromNumber:myNumber];
NSLog(@"myString: %@",myString);

myNumber = [f numberFromString:@"000"]; // Note that the extra zeros are useless
[f setFormatWidth:3];
[f setPaddingCharacter:@"0"];
myString = [f stringFromNumber:myNumber];
NSLog(@"myString: %@",myString);

NSLog输出：

myString：4.5

myString：000

myString: 4.5
myString: 000

如果你没有字符串开头只需创建数字：

If you don't have strings to start with just create number like:

myNumber = [NSNumber numberWithFloat:4.5];
myNumber = [NSNumber numberWithInt:0];

或者只是使用标准格式：

Or just use standard formatting:

myString = [NSString stringWithFormat:@"%.1f", [myNumber floatValue]];
myString = [NSString stringWithFormat:@"%03d", [myNumber intValue]];

或者如果你不需要 NSNumber 表示只使用标准格式：

Or if you don't need an NSNumber representation just use standard formatting :

myString = [NSString stringWithFormat:@"%.1f", 4.5];
myString = [NSString stringWithFormat:@"%03d", 0];

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