OC基础：NSDictionary

NSDictionary 使用总结:

1.工厂方法创建字典：

#pragma mark - 创建字典(+)
-(void)Creating
{
    //空字典
    NSDictionary *dictionary = [NSDictionary dictionary];
    // 测试数据
    NSString *filePath = [self testData];
    
    // 通过文件路径创建字典
    dictionary = [NSDictionary dictionaryWithContentsOfFile:filePath];
    dictionary = [NSDictionary dictionaryWithContentsOfURL:[NSURL fileURLWithPath:filePath]];
    
    //通过字典生成一个新的字典
    dictionary = [NSDictionary dictionaryWithDictionary:dictionary];
    
    // 生成只有一个键-值对的字典
    dictionary = [NSDictionary dictionaryWithObject:@"value" forKey:@"key"];
    
    // 根据两个数组合并生成包含多个键-值对的字典
    NSArray *values = [NSArray arrayWithObjects:@"Hello",@"World",nil];
    NSArray *keys = [NSArray arrayWithObjects:@"key1",@"key2",nil];
    dictionary = [NSDictionary dictionaryWithObjects:values forKeys:keys];
    
    // 生成包含多个键-值对的字典。数据的顺序为value，key，nil
    dictionary = [NSDictionary dictionaryWithObjectsAndKeys:@"Hello",@"key1",@"World",@"Key2", nil];
    
    
    dictionary = @{@"key1":@"Hello",@"key2":@"World"};
}

2.初始化创建字典

-(void)Initializing
{
    // 空字典
    NSDictionary *dictionary = [[NSDictionary alloc] init];
    
    // 测试数据
    NSString *filePath = [self testData];
    
    // 通过文件路径创建字典
    dictionary = [[NSDictionary alloc] initWithContentsOfURL:[NSURL fileURLWithPath:filePath]];
    dictionary = [[NSDictionary alloc] initWithContentsOfFile:filePath];
    
    // 通过字典生成一个新的字典
    dictionary = [[NSDictionary alloc] initWithDictionary:dictionary];
    dictionary = [[NSDictionary alloc] initWithDictionary:dictionary copyItems:YES];

    // 根据两个数组合并生成包含多个键-值对的字典
    NSArray *values = [NSArray arrayWithObjects:@"Hello", @"World", nil];
    NSArray *keys = [NSArray arrayWithObjects:@"key1", @"key2", nil];
    dictionary = [[NSDictionary alloc] initWithObjects:values forKeys:keys];
    
    
    // 生成包含多个键-值对的字典。数据的顺序为value，key，nil
    dictionary = [[NSDictionary alloc] initWithObjectsAndKeys:@"Hello", @"key1", @"World", @"key2", nil];
}

3.计算个数:

#pragma mark 计算个数
-(void)CountingEntries
{
    NSDictionary *dictionary = [NSDictionary dictionaryWithObjectsAndKeys:@"Hello",@"Key1",@"World",@"Key2", nil];
     // 字典内的key-value个数,
    NSUInteger count = dictionary.count;
    NSLog(@"count:%lu",(unsigned long)count);
}

4.比较：

#pragma mark 比较
-(void)ComparingDictionaries
{
    NSDictionary *dictionary = [NSDictionary dictionaryWithObjectsAndKeys:@"Hello",@"Key1",@"World",@"Key2",nil];
    
    NSDictionary *dictionary1 = [NSDictionary dictionaryWithObjectsAndKeys:@"Hello",@"Key1",@"World",@"Key2",nil];
    
    // 比较字典中的数据是否一致
    BOOL isEqual = [dictionary isEqualToDictionary:dictionary1];
    NSLog(@"isEqualToDictionary:%d", isEqual);// out 1
    
}

5.访问键和值

#pragma mark 访问键和值
-(void)AccessKeysAndValues
{
    NSDictionary *dictionary = @{@"Key1":@"Hello",@"Key2":@"World"};
    
    // 所有的keys
    NSArray *keys = dictionary.allKeys;
    
    NSLog(@"keys:%@",keys);
    
    // 根据value获取keys，可能多个key指向
    keys = [dictionary allKeysForObject:@"Hello"];
    
    // 所有的values
    NSArray *values = dictionary.allValues;
    
     NSLog(@"values:%@",values);
    
    // 根据key提取value
    NSString *value = [dictionary objectForKey:@"Key1"];
    value = [dictionary valueForKey:@"Key2"];
    value = [dictionary objectForKeyedSubscript:@"Key1"];
    
    // 根据多个key获取多个value,如果没找到
    values = [dictionary objectsForKeys:keys notFoundMarker:@"NotFound"];
    
}

6.遍历

#pragma mark 遍历
-(void)Enumerating
{
    NSDictionary *dictionary = @{@"Key1":@"Hello",@"Key2":@"World"};
    //遍历keys
    NSEnumerator *enumerator = [dictionary keyEnumerator];
    id key;
    while (key = [enumerator nextObject]) {
        NSLog(@"key:%@",key);
    }
    
    // 遍历values
    enumerator = [dictionary objectEnumerator];
    id value;
    while (value = [enumerator nextObject]) {
        NSLog(@"value:%@",value);
    }
    
    // 快速遍历key,value
    for (id key in dictionary) {
        id value = [dictionary objectForKey:key];
        NSLog(@"%@=%@", key, value);
    }
    
    // key-value遍历
    [dictionary enumerateKeysAndObjectsUsingBlock:^(id  _Nonnull key, id  _Nonnull obj, BOOL * _Nonnull stop) {
        NSLog(@"key:%@; value:%@", key, obj);
        *stop = YES;// 当stop设为YES时，会停止遍历
    }];
    
    [dictionary enumerateKeysAndObjectsWithOptions:NSEnumerationReverse usingBlock:^(id  _Nonnull key, id  _Nonnull obj, BOOL * _Nonnull stop) {
        NSLog(@"key:%@; value:%@", key, obj);
       // *stop = YES;// 当stop设为YES时，会停止遍历,必须设NSEnumerationReverse
    }];
}

7.排序

#pragma mark 排序
-(void)Sorting
{
    NSDictionary *dictionary = @{@"Key1":@"Hello",@"Key2":@"World"};
    
    // 使用Selector比较获取key, compare:由对象去实现
    NSArray *array = [dictionary keysSortedByValueUsingSelector:@selector(compare:)];
    
    // 使用block比较value,排序key
    array = [dictionary keysSortedByValueUsingComparator:^NSComparisonResult(id  _Nonnull obj1, id  _Nonnull obj2) {
        return [obj1 compare:obj2];
    }];
    
    
    array = [dictionary keysSortedByValueWithOptions:NSSortStable usingComparator:^NSComparisonResult(id  _Nonnull obj1, id  _Nonnull obj2) {
        return [obj1 compare:obj2];
    }];

}

8.过滤

#pragma mark 过滤
-(void)Filtering
{
    NSDictionary *dictionary = @{@"Key1":@"Hello",@"Key2":@"World"};
    
    // 返回过滤后的keys
    NSSet *set = [dictionary keysOfEntriesPassingTest:^BOOL(id  _Nonnull key, id  _Nonnull obj, BOOL * _Nonnull stop) {
        // stop 是否停止过滤
        // return 通过yes，禁止no
        return YES;
    }];
    
    // 多核过滤
    set = [dictionary keysOfEntriesWithOptions:NSEnumerationConcurrent passingTest:^BOOL(id  _Nonnull key, id  _Nonnull obj, BOOL * _Nonnull stop) {
        // stop 是否停止过滤
        // return 通过yes，禁止no
        return YES;
    }];
}

9.存储到文件

-(void)Storing
{
    NSDictionary *dictionary = @{@"Key1":@"Hello",@"Key2":@"World"};
    NSString *filePath = [self testData];
    
    // 根据路径存储字典
    BOOL write = [dictionary writeToFile:filePath atomically:YES];
    
    write = [dictionary writeToURL:[NSURL fileURLWithPath:filePath] atomically:YES];
    [dictionary fileCreationDate]; 
}

10.访问文件属性

#pragma mark 访问文件属性
- (void)AccessingFileAttributes {
    
    NSString *filePath = [self testData];

    NSError *error;
    NSDictionary *dictionary = [[NSFileManager defaultManager] attributesOfItemAtPath:filePath error:&error];
    
    NSLog(@"创建时间:%@", dictionary.fileCreationDate);
    NSLog(@"是否可见:%d", dictionary.fileExtensionHidden);
    NSLog(@"组ID:%@", dictionary.fileGroupOwnerAccountID);
    NSLog(@"组名:%@", [dictionary fileGroupOwnerAccountName]);
    NSLog(@"HFS编码:%u", (unsigned int)dictionary.fileHFSCreatorCode);
    NSLog(@"HFS类型编码:%u", (unsigned int)dictionary.fileHFSTypeCode);
    NSLog(@"是否只读:%d", dictionary.fileIsAppendOnly);
    NSLog(@"是否可修改:%d", dictionary.fileIsImmutable);
    NSLog(@"修改时间:%@", dictionary.fileModificationDate);
    NSLog(@"所有者ID:%@", dictionary.fileOwnerAccountID);
    NSLog(@"所有者名:%@", dictionary.fileOwnerAccountName);
    NSLog(@"Posix权限:%lu", (unsigned long)dictionary.filePosixPermissions);
    NSLog(@"大小:%llu", dictionary.fileSize);
    NSLog(@"系统文件数量:%lu", (unsigned long)dictionary.fileSystemFileNumber);
    NSLog(@"文件系统的数量:%ld", (long)dictionary.fileSystemNumber);
    NSLog(@"文件类型:%@", dictionary.fileType);
    
}

11.可变字典初始化:

#pragma mark 初始化
-(void)CreatingAndInitializing
{
    // 创建包含一个key-value的可变字典。
    NSMutableDictionary *mDictionary = [NSMutableDictionary dictionaryWithCapacity:1];
    mDictionary = [[NSMutableDictionary alloc] initWithCapacity:1];
    
    // 空字典
    mDictionary = [NSMutableDictionary dictionary];
    mDictionary = [[NSMutableDictionary alloc] init];
}

12.可变字典添加元素

-(void)AddingEntries
{
    NSMutableDictionary *mDictionary = [NSMutableDictionary dictionary];
    
    //增加单一记录
    [mDictionary setObject:@"Hello" forKey:@"Key1"];
    [mDictionary setObject:@"World" forKeyedSubscript:@"Key2"];
    [mDictionary setValue:@"Lucy" forKey:@"Key3"];
    
    NSLog(@"%@",mDictionary);
    
    // 从字典中增加数据
    NSDictionary *dictionary = [NSDictionary dictionaryWithObject:@"IOS" forKey:@"Key4"];
    [mDictionary addEntriesFromDictionary:dictionary];
    NSLog(@"%@",mDictionary);
    
    // 用新的字典数据覆盖原有字典数据
    [mDictionary setDictionary:dictionary];
    NSLog(@"%@",mDictionary);
    
}

13.可变字典删除元素

#pragma mark 删除记录
-(void)RemovingEntries
{
    NSMutableDictionary *mDictionary = [NSMutableDictionary dictionary];
    
    //增加单一记录
    [mDictionary setObject:@"Hello" forKey:@"Key1"];
    [mDictionary setObject:@"World" forKeyedSubscript:@"Key2"];
    [mDictionary setValue:@"Lucy" forKey:@"Key3"];
    [mDictionary setValue:@"IOS" forKey:@"Key4"];
    
    NSLog(@"%@",mDictionary);
    
    // 根据key删除单一记录
    [mDictionary removeObjectForKey:@"Key1"];
    
    NSLog(@"%@",mDictionary);
    
    // 批量删除多个key对应的记录
    NSArray *keys = [NSArray arrayWithObjects:@"Key2",@"Key3",nil];
    [mDictionary removeObjectsForKeys:keys];
    NSLog(@"%@",mDictionary);
    
    // 删除所有记录
    [mDictionary removeAllObjects];
    NSLog(@"%@",mDictionary);
    
}

demo地址：demo

OC基础：NSDictionary

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