OC06 -- 字典

一. 创建不可变字典的方式:

//字典的字面量,前key后value

NSDictionary *dic =@{@"1":@"2",@"3":@"4"};

NSDictionary *dic = [[NSDictionaryalloc]init];

NSDictionary *dic = [NSDictionary dictionary];

NSDictionary *dic = [[NSDictionary alloc]initWithObjectsAndKeys:@"1",@"2",@"3",@"4",@"5",@"6",@"7",@"8",nil];

NSLog(@"%@",dic);

// Key 是唯一的,可是Value是能够反复的

// key 不能为空.

二. 不可变字典的属性与方法:

//1.属性:有多少键值对 -- count:

NSLog(@"%ld",dic.count);

// 2. objectForKey --
依据Key找value:

NSLog(@"%@",[dic objectForKey:@"2"]);

NSLog(@"%@",dic[@"2"]);

//3. 获取全部的key和value --

NSLog(@"%@",dic.allKeys);

NSLog(@"%@",dic.allValues);

三. 创建可变字典的方式:

NSMutableDictionary *dic = [NSMutableDictionarydictionaryWithObjectsAndKeys:@"1",@"2",@"3",@"4",@"5",@"6",nil];

//
遍历字典.

打出全部Vaule

for (NSInteger i =
; i < dic.allKeys.count; i++) {

NSLog(@"%@",dic.allValues[i]);

}

for (NSString *str
in dic) {

NSLog(@"%@",str);//
打出字典的Key.

NSLog(@"%@",dic[str]);//打出Vaule.

}

四.可变字典的属性与方法:

NSMutableDictionary *dic1 = [[NSMutableDictionaryalloc]initWithObjectsAndKeys:@"1",@"2",@"3",@"4",@"5",@"6",@"7",@"8",nil];

//1.可变键值对加入(当key不存在时就进行加入,当key存在时,就进行vaule值的改动.)
-- setObject forKey:

[dic1setObject:@"10"forKey:@"11"];

NSLog(@"%@\n",dic1);

[dic1setObject:@"1000"forKey:@"11"];

NSLog(@"%@",dic1);

//2. 移除键值对

[dic1 removeObjectForKey:@"8"];

NSLog(@"%@",dic1);

//3. 所有移除

[dic1 removeAllObjects];

NSLog(@"%@",dic1);

//4. setObject
是字典自己方法,setVaule是KVC的方法,即使效果一样,但以后对字典进行操作还用setObject.

[dic1setValue:@"100"forKey:@"10"];

五.字典与数组的嵌套:

//1. 字典里对象是数组.

NSArray *arr1 =
@[@"1",@"2",@"3",@"4"];

NSArray *arr2 =
@[@"5",@"6",@"7",@"8"];

NSMutableDictionary *dic = [NSMutableDictionarydictionaryWithObjectsAndKeys:arr1,@"arr1",arr2,@"arr2",nil];

//
遍历.

for (NSString *keyin dic) {

//
针对相应的key 找到vaule,vaule是一个数组,所以用一个数组对象来接受.

NSLog(@"%@",key);

NSArray *arr = dic[key];

for (NSString *vaulein arr) {

NSLog(@"%@",vaule);

}

}

//2. 数组里对象是字典.

NSDictionary *dic1 = [NSDictionarydictionaryWithObjectsAndKeys:@"杨林",@"name",@"19",@"age",nil];

NSDictionary *dic2 = [NSDictionarydictionaryWithObjectsAndKeys:@"刘鑫狗",@"name",@"20",@"age",nil];

NSDictionary *dic3 = [NSDictionarydictionaryWithObjectsAndKeys:@"刘伊茹",@"name",@"0",@"age",nil];

NSArray *arr =
@[dic1,dic2,dic3];

for (NSDictionary *dicin arr) {

for (NSString *keyin dic) {

NSLog(@"%@",dic[key]);

}

}

六.三层嵌套的练习:

NSDictionary *dic1 = [NSDictionarydictionaryWithObjectsAndKeys:@"杨林",@"name",@"19",@"age",nil];

NSDictionary *dic2 = [NSDictionarydictionaryWithObjectsAndKeys:@"刘鑫狗",@"name",@"20",@"age",nil];

NSDictionary *dic3 = [NSDictionarydictionaryWithObjectsAndKeys:@"刘伊茹",@"name",@"0",@"age",nil];

NSArray *arr1 =
@[dic1,dic2];

NSArray *arr2 =
@[dic3];

NSDictionary *Bdic = [NSDictionarydictionaryWithObjectsAndKeys:arr1,@"arr1",arr2,@"arr2",nil];

for (NSString *keyBin Bdic) {

NSArray *arr =Bdic[keyB];

for (NSDictionary *sdicin arr) {

for (NSString *keyin sdic) {

NSLog(@"%@",sdic[key]);

}

}

}