//Dictionary
//不可变
//字典里面：是以键值对存放的
//字典存放顺序是无序的
//字典里面：value可以重复，但key不能重复
//字典里面：key一般用字符串表示，value可用不同的对象来填充
NSDictionary *dic1 = [[NSDictionary alloc] initWithObjectsAndKeys:@"zhangsan" , @"lisi" , @"zhangxiahua" , @"wangdahua" , @"zhaoxiaojie" , @"liuhuaixuan" , nil];
NSLog(@"%@" , dic1);
NSLog(@"%ld" , [dic1 count]);
//获取一个字典当中所有的key值
//存放了所有key值的array
NSArray *keyArray = [dic1 allKeys];
for (int i = 0; i < [dic1 count]; i++) {
NSLog(@"%@" , [dic1 objectForKey:[keyArray objectAtIndex:i]]);
// NSLog(@"%@" , [dic1 objectForKey:[[dic1 allKeys] objectAtIndex:i]]);
}
NSDictionary *dic2 = [[NSDictionary alloc] initWithObjectsAndKeys:@"value1", @"key1" , @"value2" , @"key2" , @"value3" , @"key3" , nil];
NSLog(@"%@" , dic2);
//通过key数组和value数组， 快速创建字典
NSArray *keyArray1 = @[@"key1" , @"key2" , @"key3"];//OC数组方便写法
// NSLog(@"%@" , keyArray);
NSArray *valueArray = @[@"value1" , @"value2" , @"value3"];
// NSLog(@"%@" , valueArray);
NSDictionary *dic3 = [[NSDictionary alloc] initWithObjects:valueArray forKeys:keyArray1];
NSLog(@"%@" , dic3);
NSMutableDictionary 是NSDictionary的子类，所以继承了NSDictionary的方法。
[NSMutableDictionary dictionaryWithCapacity:1] : 创建一个可变词典初始指定它的长度为1.，动态的添加数据如果超过1这个词典长度会自动增加，所以不用担心数组越界。推荐用这种方式
[NSMutableDictionary initWithCapacity:10] :只是初始化一个词典的长度为10。
[dictionary setObject:@"taotao" forKey:@"name"] :向可变的词典动态的添加数据 ，这里的key是name ，值是taotao。如果词典中存在这个KEY的数据则直接替换这个KEY的值。（易混的地方，慎重！）
[dictionary removeAllObjects..] : 删除掉词典中的所有数据。
[dictionary removeObjectForKey..] :删除掉词典中指定KEY的数据 。
//字典快速写法
NSDictionary *dic4 = @{@"key1":@"value1" , @"key2":@"value2" , @"key3":@"value"};
NSLog(@"%@" , dic4);
Person *p1 = [Person personWithName:@"ren"];
Student *s2 = [Student personWithName:@"xues"];
Teacher *t3 = [Teacher personWithName:@"sdhdsjh"];
NSDictionary *dic = @{@"key1":p1 , @"key2":s2 , @"key3":t3};
NSLog(@"%@" , dic);
常用方法
获取字典数量
NSInteger count = [dic count];
通过key获取对应的value对象
NSObject *valueObj = [dic objectForKey:@"key"];
将字典的key转成枚举对象，用于遍历
NSEnumerator *enumerator = [dic keyEnumerator];
获取所有键的集合
NSArray *keys = [dic allKeys];
获取所有值的集合
NSArray *values = [dic allValues];
初始化一个空的可变字典
NSMutableDictionary *dic2 = [NSMutableDictionary dictionaryWithObjectsAndKeys:@"v1",@"key1",@"v2",@"key2",nil];
NSDictionary *dic3 = [NSDictionary dictionaryWithObject:@"v3" forKey:@"key3"];
向字典2对象中添加整个字典对象3
[dic2 addEntriesFromDictionary:dic3];
向字典2对象中最佳一个新的key3和value3
[dic2 setValue:@"value3" forKey:@"key3"];
初始化一个空的可变字典
NSMutableDictionary *dic1 = [NSMutableDictionary dictionary];
将空字典1对象内容设置与字典2对象相同
[dic1 setDictionary:dic2];
将字典中key1对应的值删除
[dic1 [email protected]"key1"];
NSArray *array = [NSArray arrayWithObjects:@"key1", nil];
根据指定的数组（key）移除字典1的内容
[dic2 removeObjectsForKeys:array];
移除字典所有对象
[dic1 removeAllObjects];
//创建一个可变字典
// 用指定空间大小来初始化
NSMutableDictionary *dic1 = [[NSMutableDictionary alloc] initWithCapacity:1];
Person *p1 = [Person personWithName:@"hdilo" andAge:23];
Person *p2 = [Person personWithName:@"hsdsf" andAge:13];
Person *p3 = [Person personWithName:@"bhycu" andAge:56];
Person *p4 = [Person personWithName:@"yusyt" andAge:67];
Person *p5 = [Person personWithName:@"yhudh" andAge:345];
//增
//从一个字典当中拿出放到别的字典里
//[mdic1 addEntriesFromDictionary:mdic2];
[mdic1 setValue:p1 forKey:@"pingguo"];
[mdic1 setValue:p2 forKey:@"dage"];
[mdic1 setValue:p3 forKey:@"haha"];
[mdic1 setValue:p4 forKey:@"hehe"];
//删
[mdic1 removeObjectForKey:@"dage"];
//按照一组key值进行删除
//用mutableCopy方法，将一个不可变的东西转换成一个可变的东西
//NSMutableDictionary *allkey = [[mdic1 allKeys] mutableCopy];
//改
//当给一个字典设定一对值的话 ，如果字典当中已经存在这个key值，就直接把原来key值当中对应的元素替换掉
//如果没有对应key值，就增加这一对设定的值
[mdic1 setValue:p5 forKey:@"hehe"];
[mdic1 setValue:p5 forKey:@"dede"];
//查
//根据key来查找一个value
Person *p6 = [mdic1 objectForKey:@"haha"];
NSLog(@"%@" , p6);
NSLog(@"%@" , mdic1);
遍历字典
快速枚举
for (id key in dic){
id obj = [dic objectForKey:key];
NSLog(@"%@", obj);
}
一般枚举
NSArray *keys = [dic allKeys];
inr length = [keys count];
for (int i = 0; i < length；i++){
id key = [keys objectAtIndex:i];
id obj = [dic objectForKey:key];
NSLog(@"%@", obj);
}
通过枚举类型枚举
NSEnumerator *enumerator = [dic keyEnumerator];
id key = [enumerator nextObject];
while (key) {
id obj = [dic objectForKey:key];
NSLog(@"%@", obj);
key = [enumerator nextObject];
}