objective-c 中数据类型之五 数值类（NSNumber及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
// num.objCType 代表类型编码@encode(type-name)
// 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"];
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
原文转自：http://blog.csdn.net/yanglishuan/article/details/40040771
