// Values of the individual days as powers of two
enum {
kMonday = 64,
kTuesday = 32,
kWednesday = 16,
kThursday = 8,
kFriday = 4,
kSaturday = 2,
kSunday = 1,
};
将所有 127 天的变体转换为人类可读字符串的最快方法是什么？
例如，如果我得到数字 7，我想输出“Fri-Sunday”
如果我得到数字 66，我想输出“周一，周六”
基本上你有两个选择：
创建一个工厂，您交出合并天数的整数，您将取回字符串
创建包装器对象，包装 int 并提供访问内部逻辑的方法
我写了一个包装器：
#import <Foundation/Foundation.h>
typedef NS_OPTIONS(NSUInteger, WeekDays) {
kMonday = 1 << 6,
kTuesday = 1 << 5,
kWednesday = 1 << 4,
kThursday = 1 << 3,
kFriday = 1 << 2,
kSaturday = 1 << 1,
kSunday = 1 << 0
};
@interface DaysWrapper : NSObject
-(id)initWithDays:(WeekDays)weekDays;
@end
@interface DaysWrapper ()
@property (nonatomic,retain) NSMutableArray *days;
@end
@implementation DaysWrapper{
int internalDays;
}
+(instancetype)dayWrapperWithDayBitmask:(WeekDays)daybits
{
return [[DaysWrapper alloc] initWithDays:daybits];
}
-(instancetype)initWithDays:(WeekDays)weekDays
{
if (self = [super init]) {
WeekDays wholeWeek = 127;
internalDays = weekDays & wholeWeek;
_days = [@[] mutableCopy];
while (wholeWeek) {
wholeWeek >>= 1;
if (weekDays & (wholeWeek +1)) {
[_days addObject:[NSNumber numberWithBool:YES]];
} else {
[_days addObject:[NSNumber numberWithBool:NO]];
}
}
}
return self;
}
-(NSString *)description
{
static dispatch_once_t onceToken;
static NSArray *dayNames;
static NSDictionary *fullnamesForDayNames;
dispatch_once(&onceToken, ^{
dayNames = @[@"Mon", @"Tues", @"Wend",@"Thu", @"Fri",@"Sat", @"Sun"];
fullnamesForDayNames = [[NSDictionary alloc] initWithObjects: @[@"Monday",@"Tuesday",@"Wendsday",@"Thursday",@"Friday",@"Saturday",@"Sunday"]
forKeys:dayNames];
});
NSMutableString *returnSting = [@"" mutableCopy];
__block BOOL previousWasAvailable = NO;
NSMutableArray *dayRanges = [@[] mutableCopy];
[self.days enumerateObjectsUsingBlock:^(id obj, NSUInteger idx, BOOL *stop) {
if (!previousWasAvailable && [obj boolValue])
[dayRanges addObject:[@[] mutableCopy]];
if ([obj boolValue]) {
NSMutableArray *actualRange = [dayRanges lastObject];
[actualRange addObject:dayNames[idx]];
}
previousWasAvailable = [obj boolValue];
}];
[dayRanges enumerateObjectsUsingBlock:^(NSMutableArray *rangeArray, NSUInteger idx, BOOL *stop) {
if ([returnSting length]){
[returnSting appendString:@","];
}
if ([rangeArray count] > 1) {
[returnSting appendString: [rangeArray firstObject]];
if ([rangeArray count] > 2){
[returnSting appendString:@"-"];
} else {
[returnSting appendString:@","];
}
}
if (idx == [dayRanges count]-1){
[returnSting appendString: fullnamesForDayNames[[rangeArray lastObject]]];
} else {
[returnSting appendString:[rangeArray lastObject]];
}
}];
return returnSting;
}
@end
int main(int argc, const char * argv[])
{
@autoreleasepool {
WeekDays monAndFriday = kMonday | kFriday;
WeekDays thurToSat = kThursday | kFriday | kSaturday;
WeekDays weekEnd = kFriday | kSaturday | kSunday;
WeekDays mondAndWeekend = weekEnd | kMonday;
WeekDays friSat = kFriday | kSaturday;
WeekDays everySecondDay = 8 | 32 | 2;
WeekDays moday = kMonday;
WeekDays workWeek = kMonday | kTuesday | kWednesday | kThursday | kFriday;
WeekDays wholeWeek = workWeek | weekEnd;
WeekDays notThursday = ~kThursday & wholeWeek;
NSLog(@"%@", [DaysWrapper dayWrapperWithDayBitmask:monAndFriday]);
NSLog(@"%@", [DaysWrapper dayWrapperWithDayBitmask:weekEnd]);
NSLog(@"%@", [DaysWrapper dayWrapperWithDayBitmask:thurToSat]);
NSLog(@"%@", [DaysWrapper dayWrapperWithDayBitmask:mondAndWeekend]);
NSLog(@"%@", [DaysWrapper dayWrapperWithDayBitmask:friSat]);
NSLog(@"%@", [DaysWrapper dayWrapperWithDayBitmask:everySecondDay]);
NSLog(@"%@", [DaysWrapper dayWrapperWithDayBitmask:moday]);
NSLog(@"%@", [DaysWrapper dayWrapperWithDayBitmask:workWeek]);
NSLog(@"%@", [DaysWrapper dayWrapperWithDayBitmask:wholeWeek]);
NSLog(@"%@", [DaysWrapper dayWrapperWithDayBitmask:notThursday]);
}
return 0;
}
输出
Mon,Friday
Fri-Sunday
Thu-Saturday
Mon,Fri-Sunday
Fri,Saturday
Tues,Thu,Saturday
Monday
Mon-Friday
Mon-Sunday
Mon-Wend,Fri-Sunday
随意的想法
self.days，您可以在每次需要时动态处理它以减少空间通用代码大修（ARC、现代 obj-c 语法、NS_OPTIONS、……）2015 年 5 月 21 日
这是一个有趣的挑战。
#import <Foundation/Foundation.h>
enum {
kMonday = 1 << 0,
kTuesday = 1 << 1,
kWednesday = 1 << 2,
kThursday = 1 << 3,
kFriday = 1 << 4,
kSaturday = 1 << 5,
kSunday = 1 << 6,
};
typedef int DayBits;
NSString * const shortDayNames[] = { @"Mon", @"Tues", @"Wed", @"Thurs", @"Fri", @"Sat", @"Sun" };
NSString * const fullDayNames[] = { @"Monday", @"Tuesday", @"Wednesday", @"Thursday", @"Friday", @"Saturday", @"Sunday" };
int main(int argc, const char * argv[])
{
@autoreleasepool {
// Demo all possible combinations
for( DayBits days_as_bits = 0; days_as_bits < 128; days_as_bits++ ){
// Create an index set from the bits
NSMutableIndexSet * indexes = [NSMutableIndexSet indexSet];
for( int bit = 0; bit < 7; bit++ ){
if( days_as_bits & (1 << bit) ){
[indexes addIndex:bit];
}
}
// Create string for result
NSMutableString * daysDesc = [NSMutableString string];
// Enumerate the index set backwards and build up the string
__block BOOL contiguous = NO;
[indexes enumerateIndexesWithOptions:NSEnumerationReverse
usingBlock:^(NSUInteger idx, BOOL *stop) {
// Use short names unless this is the name that will appear
// at the end of the string
NSString * const * dayNames = shortDayNames;
if (0 == [daysDesc length]) {
dayNames = fullDayNames;
}
// If the previous index is present, we're working on a contiguous set
if( [indexes containsIndex:(idx - 1)] ){
// If we were already in a contiguous set, just continue
if( contiguous ){
return;
}
// This is the end day of a contiguous set; place the name
// and a hyphen
else {
[daysDesc insertString:[NSString stringWithFormat:@"-%@", dayNames[idx]]
atIndex:0];
contiguous = YES;
return;
}
}
// We've reached the start day of a set.
// Turn off contiguous and fall through
else {
contiguous = NO;
}
// Place a comma and today's name
[daysDesc insertString:[NSString stringWithFormat:@", %@", dayNames[idx]]
atIndex:0];
}];
// Clean up extraneous comma and space at the beginning of the string
daysDesc = [daysDesc stringByTrimmingCharactersInSet:[NSCharacterSet characterSetWithCharactersInString:@" ,"]];
NSLog(@"%d: %@", days_as_bits, daysDesc);
}
}
return 0;
}
请注意，我调换了您enum的位置以使其正常工作，因此这实际上对您来说可能完全没用，但希望对您有所帮助。这意味着，例如， 7kMonday | kTuesday | kWednesday代替kFriday | kSaturday | kSunday，所以结果是Mon-Wed。
我认为索引集的使用可能是我必须提供的主要见解。
您也许可以通过一些工作来切换事物（取消反转枚举等）；我已经浪费了足够多的时间了^W^W^W满足了我对此的好奇。