////  main.m//  NSDictionary////#import 
     
      int main(int argc, const char * argv[]) {    // 1.如何创建    NSDictionary *dict1 = [NSDictionary dictionaryWithObject:@"lnj" forKey:@"name"];    NSString *name1 = [dict1 objectForKey:@"name"];    NSLog(@"name = %@", name1); //lnj    NSLog(@"dict1 = %@", dict1);    //dict1 = {name = lnj;}                // 注意: key和value 是一一对应    NSDictionary *dict2 = [NSDictionary dictionaryWithObjects:@[@"lnj", @"30", @"1.75"] forKeys:@[@"name", @"age", @"height"]];    NSLog(@"dict2 = %@", dict2);    //{age = 30;height = "1.75";name = lnj;}    NSLog(@"%@ %@ %@", [dict2 objectForKey:@"name"], [dict2 objectForKey:@"age"], [dict2 objectForKey:@"height"]);        //NSDictionary *dict3 = @{key:value};    NSDictionary *dict4 = @{
   @"name": @"lnj"};    NSLog(@"%@", dict4[@"name"]);        NSDictionary *dict5 = @{
   @"name":@"lnj", @"age":@"30", @"height":@"1.75"};    NSLog(@"dict5 = %@", dict5);//{age = 30;height = "1.75";name = lnj;}    NSLog(@"%@ %@ %@", dict5[@"name"], dict5[@"age"], dict5[@"height"]);        // 2.字典的遍历    NSDictionary *dict6 = @{
   @"name":@"lnj", @"age":@"30", @"height":@"1.75"};    // 2.1如何获取字典中key和value的个数, 在字典中key称之为键, value称之为值    NSLog(@"count = %lu", [dict6 count]);            for (int i = 0; i < dict6.count; ++i) {        // 获取字典中所有的key        NSArray *keys = [dict6 allKeys];        // 取出当前位置对应的key        NSLog(@"%@", keys[i]);        NSString *key = keys[i];        NSString *value = dict6[key];        NSLog(@"key = %@, value = %@", key, value);    }                // 如何通过forin遍历字典, 会将所有的key赋值给前面的obj    for (NSString *key in dict6) {        NSLog(@"%@", key);        NSString *value = dict6[key];        NSLog(@"key = %@, value = %@", key, value);    }                [dict6 enumerateKeysAndObjectsUsingBlock:^(id key, id obj, BOOL *stop) {        NSLog(@"key = %@, value = %@", key, obj);    }];            // 3.字典文件读写    NSDictionary *dict7 = @{
   @"name":@"lnj", @"age":@"30", @"height":@"1.75"};    // XML 扩展名plist    [dict7 writeToFile:@"/Users/mctc/Desktop/a.plist" atomically:YES];        // 注意: 字典和数组不同, 字典中保存的数据是无序的    NSDictionary *newDict8 = [NSDictionary dictionaryWithContentsOfFile:@"/Users/mctc/Desktop/a.plist"];    NSLog(@"%@", newDict8);// {age = 30;height = "1.75";name = lnj;}            NSArray *arr9 = @[@10, @20, @30, @5];    [arr9 writeToFile:@"/Users/mctc/Desktop/a.plist" atomically:YES];        return 0;}