Five numeric types in objective-C (nsnumber and nsnumberformatter)

// 聊聊NSNumber， NSNumber可以封装c中基本数据类型 char，int，long，float，BOOL，NSInteger，CGFloat等。    NSNumber *num = [NSNumber numberWithChar:'a'];    NSLog(@"%@", num); // 97        num = [NSNumber numberWithInteger:97];    num = [NSNumber numberWithFloat:97.0];    num = [NSNumber numberWithBool:YES];        // 不过直接用下面的方式封装会更方便    num = @'a';    num = @97;    num = @97.0;    num = @YES;        // 既然NSNumber能封装BOOL，NSInteger，CGFloat等基础数据格式，那如何判断NSNumber是什么基础类型呢，接着看    /*     + (NSNumber *)numberWithChar:(char)value;     + (NSNumber *)numberWithUnsignedChar:(unsigned char)value;     + (NSNumber *)numberWithShort:(short)value;     + (NSNumber *)numberWithUnsignedShort:(unsigned short)value;     + (NSNumber *)numberWithInt:(int)value;     + (NSNumber *)numberWithUnsignedInt:(unsigned int)value;     + (NSNumber *)numberWithLong:(long)value;     + (NSNumber *)numberWithUnsignedLong:(unsigned long)value;     + (NSNumber *)numberWithLongLong:(long long)value;     + (NSNumber *)numberWithUnsignedLongLong:(unsigned long long)value;     + (NSNumber *)numberWithFloat:(float)value;     + (NSNumber *)numberWithDouble:(double)value;     + (NSNumber *)numberWithBool:(BOOL)value;     + (NSNumber *)numberWithInteger:(NSInteger)value NS_AVAILABLE(10_5, 2_0);     + (NSNumber *)numberWithUnsignedInteger:(NSUInteger)value NS_AVAILABLE(10_5, 2_0);     */    num = [NSNumber numberWithChar:'a'];    NSLog(@"%@ %@", NSStringFromClass(num.class), @(num.objCType)); // __NSCFNumber c    num = [NSNumber numberWithUnsignedChar:'a'];    NSLog(@"%@ %@", NSStringFromClass(num.class), @(num.objCType)); // __NSCFNumber s    num = [NSNumber numberWithShort:97];    NSLog(@"%@ %@", NSStringFromClass(num.class), @(num.objCType)); // __NSCFNumber s    num = [NSNumber numberWithUnsignedShort:97];    NSLog(@"%@ %@", NSStringFromClass(num.class), @(num.objCType)); // __NSCFNumber i    num = [NSNumber numberWithInt:97];    NSLog(@"%@ %@", NSStringFromClass(num.class), @(num.objCType)); // __NSCFNumber i    num = [NSNumber numberWithUnsignedInt:97];    NSLog(@"%@ %@", NSStringFromClass(num.class), @(num.objCType)); // __NSCFNumber q    num = [NSNumber numberWithLong:97];    NSLog(@"%@ %@", NSStringFromClass(num.class), @(num.objCType)); // __NSCFNumber i    num = [NSNumber numberWithUnsignedLong:97];    NSLog(@"%@ %@", NSStringFromClass(num.class), @(num.objCType)); // __NSCFNumber q    num = [NSNumber numberWithLongLong:97];    NSLog(@"%@ %@", NSStringFromClass(num.class), @(num.objCType)); // __NSCFNumber q    num = [NSNumber numberWithUnsignedLongLong:97];    NSLog(@"%@ %@", NSStringFromClass(num.class), @(num.objCType)); // __NSCFNumber q    num = [NSNumber numberWithFloat:1.2];    NSLog(@"%@ %@", NSStringFromClass(num.class), @(num.objCType)); // __NSCFNumber f    num = [NSNumber numberWithDouble:1.2];    NSLog(@"%@ %@", NSStringFromClass(num.class), @(num.objCType)); // __NSCFNumber d    num = [NSNumber numberWithBool:YES];    NSLog(@"%@ %@", NSStringFromClass(num.class), @(num.objCType)); // __NSCFBoolean c    num = [NSNumber numberWithInteger:97];    NSLog(@"%@ %@", NSStringFromClass(num.class), @(num.objCType)); // __NSCFNumber i    num = [NSNumber numberWithUnsignedInteger:YES];    NSLog(@"%@ %@", NSStringFromClass(num.class), @(num.objCType)); // __NSCFNumber i        // 这样就看出来了，判断整型int类，包括short, unsigned short, int, unsigned int, long, unsigned long, long long, unsigned long long，就这样判断    NSArray *intTypeArray = @[@"s", @"i", @"q"];    NSString *intType = [NSString stringWithFormat:@"%s", num.objCType];    if ([NSStringFromClass(num.class) isEqualToString:@"__NSCFNumber"] && [intTypeArray containsObject:intType]) {        NSLog(@"%@是一个整数", num);    }    // 浮点型判断    NSArray *floatTypeArray = @[@"f", @"d"];    <pre name="code" class="objc">    NSString *floatType = [NSString stringWithFormat:@"%s", num.objCType];    if ([NSStringFromClass(num.class) isEqualToString:@"__NSCFNumber"] && [floatTypeArray containsObject:floatType]) {        NSLog(@"%@是一个浮点型", num);    }    // char判断    NSArray *charTypeArray = @[@"c"];    NSString *charType = [NSString stringWithFormat:@"%s", num.objCType];    if ([NSStringFromClass(num.class) isEqualToString:@"__NSCFNumber"] && [charTypeArray containsObject:charType]) {        NSLog(@"%@是一个字符型", num);    }    // BOOL判断    if ([NSStringFromClass(num.class) isEqualToString:@"__NSCFBoolean"]) {        NSLog(@"%@是一个字符型", num);    }    if ([num isKindOfClass:NSClassFromString(@"__NSCFBoolean")]) {        NSLog(@"num is BOOL type");    } else {        NSLog(@"num is not BOOL type");    }    // 下面聊NSNumberFormatter    // 从学号谈起，一般学号的全格式是 入学年份（前两位）+大学(学院)代码+专业代码+班级+个人班级学号 05+01+02+1+01，给班级学生列成绩单，知道学生班级学号，生成学校学号，如5号，应该生成050102105，我们想到的方法是c中的格式化，例如：    NSInteger classCode = 5;    NSString *schoolStuCode = [NSString stringWithFormat:@"0501021%2.2d", classCode];    NSLog(@"schoolStuCode = %@", schoolStuCode); // 050102105        // 另一种方法是NSNumberFormatter转换，上代码    // 数据格式转换类    NSNumberFormatter *numberFormatter = [[NSNumberFormatter alloc] init];        numberFormatter.numberStyle = kCFNumberFormatterNoStyle;    numberFormatter.formatWidth = 2;    // 数据宽度为2，不足前面补0    numberFormatter.paddingCharacter = @"0";    schoolStuCode = [NSString stringWithFormat:@"0501021%@", [numberFormatter stringFromNumber:@(classCode)]];    NSLog(@"schoolStuCode = %@", schoolStuCode); // 050102105    // 这里也输出了050102105        // 之后体验NSNumberFormatter强大功能    // 字符串分隔，可用于手机号显示    NSString *formatterStr;    numberFormatter.numberStyle = kCFNumberFormatterDecimalStyle;    formatterStr = [numberFormatter stringFromNumber:@102140302];    NSLog(@"%@", formatterStr); // 102,140,302    // 从格式字符串转换为数据，其他类似    NSNumber *number = [numberFormatter numberFromString:formatterStr];    NSLog(@"number = %@", number);    // 货币符号    numberFormatter.numberStyle = NSNumberFormatterCurrencyStyle;    formatterStr = [numberFormatter stringFromNumber:@1.2];    NSLog(@"%@", formatterStr); // $1.20    // 百分数格式    numberFormatter.numberStyle = kCFNumberFormatterPercentStyle;    formatterStr = [numberFormatter stringFromNumber:@1.2];    NSLog(@"%@", formatterStr); // 120%    // 科学计数格式    numberFormatter.numberStyle = kCFNumberFormatterScientificStyle;    formatterStr = [numberFormatter stringFromNumber:@1.2];    NSLog(@"%@", formatterStr); // 1.2E0    // 口语格式    numberFormatter.numberStyle = kCFNumberFormatterSpellOutStyle;    formatterStr = [numberFormatter stringFromNumber:@1.2];    NSLog(@"%@", formatterStr); // one point two

Five numeric types in objective-C (nsnumber and nsnumberformatter)