iOS杂记之NSNumberFormatter用法

double  testNum =3.7999;

NSNumberFormatter*formatter = [[NSNumberFormatteralloc] init];

typedef CF_ENUM(CFIndex, CFNumberFormatterRoundingMode) {

           kCFNumberFormatterRoundCeiling = 0,  //四舍五入,直接输出4

          kCFNumberFormatterRoundFloor = 1 ,    //保留小数输出3.8

          kCFNumberFormatterRoundDown = 2,  //加上了人民币标志,原值输出￥3.8

          kCFNumberFormatterRoundUp = 3,      //本身数值乘以100后用百分号表示,输出380%

          kCFNumberFormatterRoundHalfEven = 4,//输出3.799999999E0

          kCFNumberFormatterRoundHalfDown = 5,//原值的中文表示,输出三点七九九九。。。。

          kCFNumberFormatterRoundHalfUp = 6//原值中文表示,输出第四
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       /*     typedef NS_ENUM(NSUInteger, NSNumberFormatterStyle) {

            NSNumberFormatterNoStyle = kCFNumberFormatterNoStyle,    

            NSNumberFormatterDecimalStyle = kCFNumberFormatterDecimalStyle,

            NSNumberFormatterCurrencyStyle = kCFNumberFormatterCurrencyStyle,

            NSNumberFormatterPercentStyle = kCFNumberFormatterPercentStyle,

            NSNumberFormatterScientificStyle = kCFNumberFormatterScientificStyle,

            NSNumberFormatterSpellOutStyle = kCFNumberFormatterSpellOutStyle,

            NSNumberFormatterOrdinalStyle NS_ENUM_AVAILABLE(10_11, 9_0) =                         kCFNumberFormatterOrdinalStyle,

            NSNumberFormatterCurrencyISOCodeStyle NS_ENUM_AVAILABLE(10_11, 9_0) = kCFNumberFormatterCurrencyISOCodeStyle,

            NSNumberFormatterCurrencyPluralStyle NS_ENUM_AVAILABLE(10_11, 9_0) = kCFNumberFormatterCurrencyPluralStyle,

           NSNumberFormatterCurrencyAccountingStyle NS_ENUM_AVAILABLE(10_11, 9_0) = kCFNumberFormatterCurrencyAccountingStyle,
};*/
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例子：
    formatter.numberStyle = kCFNumberFormatterRoundHalfDown;
    NSLocale *locale = [[NSLocale alloc] initWithLocaleIdentifier:@"zh_Hans"];//       
    formatter.locale = locale;
    NSString*string = [formatter stringFromNumber:NSNumbernumberWithDouble: testNum]];
    NSLog(@"%@",string);};

注意：必须手机系统语言为中文的前提下才可用，如果是非中文环境需要加上中文输出限制.为准确输出，建议使用double类型

中文语言环境输出.png
英文语言环境输出.png