创建
单个创建
NSDictionary *dict = [NSDictionary dictionaryWithObjects:(NSArray *) forKeys:(NSArray<id<NSCopying>> *)];多个创建
NSDictionary *dict = [NSDictionary dictionaryWithObjects:(NSArray *) forKeys:(NSArray<id<NSCopying>> *)];快速创建和获取
//创建：键:值，多个创建用逗号隔开
//NSDictionary *dict = @{key:value}；
NSDictionary *dict = @{@"name":@"帅逼",@"":@""};//获取：和C语言数组相似，引号中是键
dict[@"key"];字典遍历
获取字典key和value的个数(key成为键，value称为值)
//获取键值对个数
[dict count];使用forin遍历
NSDictionary *dict = @{@"name1":@"帅",@"name2":@"丑"};
for (NSString *key in dict) {NSString *value = dict[key];NSLog(@"key = %@, value = %@",key, value);
}迭代器遍历
[dict enumerateKeysAndObjectsUsingBlock:^(id _Nonnull key, id _Nonnull obj, BOOL * _Nonnull stop) {NSLog(@"key = %@, value = %@", key, obj);
}];文件读写
写
[dict writeToFile:@"/Users/y1shichanganluan/Desktop/info.plist" atomically:YES];
读
NSDictionary *newdict = [NSDictionary dictionaryWithContentsOfFile:@"/Users/y1shichanganluan/Desktop/info.plist"];
//字典保存的数据是无序的
[newdict enumerateKeysAndObjectsUsingBlock:^(id _Nonnull key, id _Nonnull obj, BOOL * _Nonnull stop) {NSLog(@"key = %@, value = %@", key, obj);
}];注意打印字典和数组并不能直接打印中文，需要重写description方法，使用可变字符串拼接，然后打印
NSMutableDictionary
创建
//空的可修改字典
NSMutableDictionary *dicM = [NSMutableDictionary dictionary];添加
//增加单个
[dictM setObject:@"" forKey:@""];
//简写
dictM[@"key"] = @"vlaue";
//将一个字典添加进该字典
[dictM setValuesForKeysWithDictionary:@{@"":@"", @"":@""}];获取
继承与父类
dictM[@"key"];删除
//删除单个
[dictM removeObjectForKey:@"key"];
//删除多个，需要传入数组
[dictM removeObjectsForKeys:@[@"key1", @"key2"]];
//删除所有
[dictM removeAllObjects];修改
//使用set给相同的key赋值，新值就会覆盖旧值
[dictM setObject:@"" forKey:@""];注意
- 不能使用@{ }创建一个可变的字典
- 如果是不可变数组，那么key不能相同，后面的会覆盖前面的
