黑马程序员－－OC基础－－NSDictionary用法

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#import <Foundation/Foundation.h>

/*
字典：
key－－>value
索引－－>文字内容

里面存储的东西都是键值对

*/

int main() {
//不可变，初始化需完成赋值
NSDictionary *dict = [NSDictionary dictionaryWithObject:@"jack" forKey:@"name"];

id obj = [dict objectForKey:@"name"];

NSLog(@"%@", obj);

NSArray *keys = @[@"name",@"address"];
NSArray *objects = @[@"jack", @"北京"];

NSDictionary *dict2 = [NSDictionary dictionaryWithObjects:objects forKeys:keys];
id obj1 = [dict2 objectForKey:@"name"];

NSLog(@"%@", obj1);

NSDictionary *dict3 = [NSDictionary dictionaryWithObjectsAndKeys:@"jack", @"name",
@"北京", @"address",
@"34234234", @"qq", nil];

id obj2 = [dict3 objectForKey:@"qq"];

NSLog(@"%@", obj2);

//建议使用
NSDictionary *dict4 = @{@"name" : @"jack",
@"address" : @"北京",
@"qq" : @"4234234"};

//id obj3 = [dict4 objectForKey:@"address"];

//建议使用
id obj3 = dict4[@"address"];

NSLog(@"%@", obj3);

//返回键值对的个数
NSLog(@"%ld", dict4.count);

//可变字典
NSMutableDictionary *dict5 = [NSMutableDictionary dictionary];
//添加键值对，无序
[dict5 setObject:@"jack" forKey:@"name"];
[dict5 setObject:@"北京" forKey:@"address"];

//重复给key赋值会覆盖以前的值,字典不允许相同的key，允许有相同的object
[dict5 setObject:@"rose" forKey:@"name"];

//删除键值对
//[dict5 removeObjectForKey:@"name"];

//遍历
NSDictionary *dict6 = @{@"name" : @"tom",
@"address" : @"北京",
@"tel" : @"3423424"};
//    NSArray *Keys = [dict6 allKeys];
//
//    for (int i = 0; i<dict6.count; i++) {
//
//        NSString *key = Keys[i];
//        NSString *object = dict6[key];
//        NSLog(@"%@=%@", key, object);
//    }

//block遍历
[dict6 enumerateKeysAndObjectsUsingBlock:^(id key, id obj, BOOL *stop) {
NSLog(@"%@-%@", key, obj );

*stop = YES;

}];

return 0;
}