NSNumber的格式化

iOS SDK提供了number也可以类似date进行格式化处理，如：

NSNumberFormatter *formatter = [[[NSNumberFormatter alloc] init] autorelease];
formatter.numberStyle = NSNumberFormatterDecimalStyle;
NSString* formatStr = [formatter stringFromNumber:@(81414469)];
NSLog(@"%@",formatStr);

那么可以看到输出如下 ：811,414,469

系统提供了一下几种格式化：

typedef NS_ENUM(NSUInteger, NSNumberFormatterStyle) {
    NSNumberFormatterNoStyle = kCFNumberFormatterNoStyle,
    NSNumberFormatterDecimalStyle = kCFNumberFormatterDecimalStyle,
    NSNumberFormatterCurrencyStyle = kCFNumberFormatterCurrencyStyle,
    NSNumberFormatterPercentStyle = kCFNumberFormatterPercentStyle,
    NSNumberFormatterScientificStyle = kCFNumberFormatterScientificStyle,
    NSNumberFormatterSpellOutStyle = kCFNumberFormatterSpellOutStyle,
};

我们例子中使用的是NSNumberFormatterDecimalStyle 即 kCFNumberFormatterDecimalStyle