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