- (void)viewDidLoad {
[super viewDidLoad];
//用一个或多个键值对初始化一个字典对象,以值,键,值,键,值,键,...,nil的顺序
NSDictionary *dict = [[NSDictionary alloc] initWithObjectsAndKeys:@1,@"key1",@2,@"key2",@3,@"key3" ,nil];
NSLog(@"dict:%@",dict);
//用两个数组初始化一个字典(一个key数组,一个value数组,大小必须相等,否则崩溃
NSArray *valueArray = @[@"1",@"2",@"3"];
NSArray *keyArray = @[@"key1",@"key2",@"key"];
NSDictionary *dict2 = [[NSDictionary alloc] initWithObjects:valueArray forKeys:keyArray];
NSLog(@"dict:%@",dict2);
NSDictionary *dict3 = [[NSDictionary alloc] initWithDictionary:dict];
NSLog(@"dict:%@",dict3);
//保存字典对象内容到文件
NSString *path = @"/Users/apple/Desktop/dict.plist";
[dict writeToFile:path atomically:YES];
//从之前保存的文件读取数据到字典对象
NSDictionary *dict4 = [NSDictionary dictionaryWithContentsOfFile:path];
NSLog(@"dict4:%@",dict4);
//不可变字典一样可以字面常量初始化，key在前，value在后
NSDictionary *dict5 = @{@"key":@1,@"key1":@2,@"key3":@3};
NSLog(@"dict5:%@",dict5);
//通过指定的key来取对应的的对象，如果没有这个key,返回nil
NSNumber *num = [dict objectForKey:@"key"];
NSLog(@"num:%@",num);
//获取字典中键值对的个数
NSInteger pairCount = [dict count];
NSLog(@"pairCount:%d",pairCount);
NSArray *allkeys = [dict allKeys];
NSArray *allvalues = [dict allValues];
NSLog(@"allkeys:%@",allkeys);
NSLog(@"allvalue:%@",allvalues);
//老办法遍历
NSArray *allkeys2 = [dict2 allKeys];
NSUInteger count = [allkeys2 count];
for (int i=0; i<count; i++) {
id key = [allkeys2 objectAtIndex:i];
id value = [dict2 objectForKey:key];
NSLog(@"%@:%@",key,value);
}
//快速枚举
for(id key in dict2){
id value = [dict objectForKey:key];
NSLog(@"%@:%@",key,value);
}
//不可变字典对象
NSMutableDictionary *mdict = [[NSMutableDictionary alloc] initWithObjectsAndKeys:@1,@"key",@2,@"key2", nil];
//删除一个键－值
[mdict removeObjectForKey:@"key"];
NSLog(@"mdict:%@",mdict);
//添加一个键－值
[mdict setObject:@3 forKey:@"key3"];
NSLog(@"mdict:%@",mdict);
NSMutableDictionary *mdict2 = [[NSMutableDictionary alloc] initWithObjectsAndKeys:@1,@"key4",@2,@"key4",@3,@"key5", nil];
//将一个字典对象里的键－值添加到另一个字典对象里
[mdict2 addEntriesFromDictionary:mdict];
NSLog(@"mdcit2:%@",mdict2);
[mdict removeAllObjects];
NSLog(@"mdict:%@",mdict);
NSMutableDictionary *mdict3 = [[NSMutableDictionary alloc] initWithObjectsAndKeys:@1,@"key3",@2,@"key4",@3,@"key5", nil];
NSMutableDictionary *mdict4 =[[NSMutableDictionary alloc] initWithObjectsAndKeys:nil];
[mdict4 setDictionary:mdict3];
NSLog(@"mdict4:%@",mdict4);
NSArray *array = @[@"key4",@2,@"key4",@3,@"key5"];
[mdict3 removeObjectsForKeys:array];
//集合
NSSet *set = [[NSSet alloc] initWithObjects:@1,@2,@3, nil];
NSSet *set2 = [[NSSet alloc] initWithObjects:@3,@4,@5, nil];
//随机取一个元素
NSNumber *num2 = [set anyObject];
NSLog(@"num2:%@",num2);
//判断集合是否包含某元素
BOOL b = [set containsObject:@1];
NSLog(@"%hhd",b);
//判断两个集合是否有交集
BOOL a = [set intersectsSet:set2];
NSLog(@"%hhd",a);
//判断两集合是否相等
BOOL c = [set isEqualToSet:set];
NSLog(@"%hhd",c);
//判断一个集合是否是两一个集合的子集
BOOL d = [set isSubsetOfSet:set2];
NSLog(@"%hhd",d);
//不可变集合
NSMutableSet *mset = [[NSMutableSet alloc] initWithObjects:@1,@2,@3, nil];
NSMutableSet *mset2 = [[NSMutableSet alloc] initWithObjects:@2,@3, nil];
//[mset intersectsSet:mset2];
//[mset addObject:@4];
//[mset removeObject:@4];
//NSArray *array3 = @[@4,@5];
//[mset addObjectsFromArray:array3];
//[mset minusSet:mset2];
// [mset removeAllObjects];
[mset unionSet:mset2];
NSLog(@"%@",mset);
}