OC根本框架之-字典类型_Iphone

OC基本框架之-字典类型

分类：NSDictionary（不可变数据字典）和NSMutableDictionary（可变数据字典）

组成：

（1）由键-值(Key-Value)对组成的数据集合
?（2）任何对象(id类型)都可以作键,但一般是字符串
?（3）字典内元素无序排列,键相同的的元素不能重复

?（4）可以通过键来快速枚举

一、不可变数据字典

（1）字典的创建和初始化

 1    //1、用一个或多个键值对初始化一个字典对象: 以值,建,值,键,...,nil的顺序 2     NSDictionary *dict01=[[NSDictionary alloc] initWithObjectsAndKeys:@"key0",@"value0",@"key1",@"value1",@"key2",@"value2", nil]; 3     NSLog(@"dict01:%@",dict01); 4     NSDictionary *dict1=[NSDictionary dictionaryWithObjectsAndKeys:@123,@"key0",@456,@"key1",@678,@"key2", nil]; 5     NSLog(@"dict1:%@",dict1); 6     //2、用两个数组初始化一个字典，一个key数组，一个value数组，两个数组大小必须相等，否则Crash 7     NSArray *keyArray=@[@"name0",@"name1",@"name2"]; 8     NSArray *valueArray=@[@"hong",@"wang",@"zhao"]; 9     NSDictionary *dict02=[[NSDictionary alloc] initWithObjects:keyArray forKeys:valueArray];10     NSDictionary *dict2=[NSDictionary dictionaryWithObjects:valueArray forKeys:keyArray];11     NSLog(@"dict02:%@",dict02);12     NSLog(@"dict2:%@",dict2);13     14     //3、用一个数据字典初始化另一个数据字典15     NSDictionary *dict03=[[NSDictionary alloc] initWithDictionary:dict1];16     NSDictionary *dict3=[NSDictionary dictionaryWithDictionary:dict1];17     NSLog(@"dict03:%@",dict03);18     NSLog(@"dict3:%@",dict3);

（2）字典对象的创建和保存-文件

    //1、保存字典对象内容到文件    [dict3 writeToFile:@"/Users/apple/Desktop/tesk.txt" atomically:YES];        //2、从之前保存的文件读取数据到字典对象    NSDictionary *dict4=[NSDictionary dictionaryWithContentsOfFile:@"/Users/apple/Desktop/tesk.txt"];    NSLog(@"dict4:%@",dict4);

(3)字典对象元素的访问

 1     //1、分别获取字典的所有键、值 2     NSArray *allkeys=[dict1 allKeys]; 3     NSLog(@"allkeys:%@",allkeys); 4     NSArray *allvalues=[dict1 allValues]; 5     NSLog(@"allvalues:%@",allvalues); 6      7     //2、通过指定的key取对应的value对象,没有这个key的话.返回nil 8     NSNumber *num1 = [dict1 objectForKey:@"key1"]; 9     NSNumber *num2 = [dict1 objectForKey:@"key5"];10     NSLog(@"%@",num1);11     NSLog(@"%@",num2);12     13     //3、获取字典中键值对的个数14     NSUInteger paircount=[dict2 count];15     NSLog(@"%lu",paircount);

（4）字典的遍历

1     for (id key in dict1) {2         id value=[dict1 objectForKey:key];3         NSLog(@"%@=%@",key,value);4     }

2015-04-07 21:17:53.933 NSDictionary[5465:226991] dict01:{    value0 = key0;    value1 = key1;    value2 = key2;}2015-04-07 21:17:53.934 NSDictionary[5465:226991] dict1:{    key0 = 123;    key1 = 456;    key2 = 678;}2015-04-07 21:17:53.934 NSDictionary[5465:226991] dict02:{    hong = name0;    wang = name1;    zhao = name2;}2015-04-07 21:17:53.934 NSDictionary[5465:226991] dict2:{    name0 = hong;    name1 = wang;    name2 = zhao;}2015-04-07 21:17:53.935 NSDictionary[5465:226991] dict03:{    key0 = 123;    key1 = 456;    key2 = 678;}2015-04-07 21:17:53.935 NSDictionary[5465:226991] dict3:{    key0 = 123;    key1 = 456;    key2 = 678;}2015-04-07 21:17:53.937 NSDictionary[5465:226991] dict4:{    key0 = 123;    key1 = 456;    key2 = 678;}2015-04-07 21:17:53.938 NSDictionary[5465:226991] allkeys:(    key1,    key0,    key2)2015-04-07 21:17:53.938 NSDictionary[5465:226991] allvalues:(    456,    123,    678)2015-04-07 21:17:53.938 NSDictionary[5465:226991] num1:4562015-04-07 21:17:53.938 NSDictionary[5465:226991] num2:(null)2015-04-07 21:17:53.938 NSDictionary[5465:226991] 键值对个数：32015-04-07 21:17:53.938 NSDictionary[5465:226991] key1=4562015-04-07 21:17:53.938 NSDictionary[5465:226991] key0=1232015-04-07 21:17:53.938 NSDictionary[5465:226991] key2=678

运行结果分析

二、可变数据字典

//可变数据字典初始化

NSMutableDictionary *mDict1=[NSMutableDictionary dictionaryWithObjectsAndKeys:@"aaa",@"name0",@"bbb",@"name1",@"ccc",@"name2", nil];

NSLog(@"%@",mDict1);

//1、加入元素到NSMutableDictionary中（注意：当key值中存在要添加的键值对中的key值时，则添加，否则覆盖）

[mDict1 setObject:@"ddd" forKey:@"name3"];

[mDict1 setObject:@"eee" forKey:@"name1"];

NSLog(@"add: %@",mDict1);

//2、查看中所有元素个数：

NSLog(@"%lu",mDict1.count);

NSNumber *num3 =[mDict1 objectForKey:@"name1"];

NSLog(@"%@",num3);

NSNumber *num4 = [mDict1 objectForKey:@"name10"];

NSLog(@"%@",num4);

//3、添加其他NSMutableDictionary

[mDict1 setValuesForKeysWithDictionary:dict1];

NSLog(@"++++%@",mDict1);

//4、根据key值删除

[mDict1 removeObjectForKey:@"name1"];

NSLog(@"---%@",mDict1);

//5、删除所有

[mDict1 removeAllObjects];

NSLog(@"%@",mDict1);

2015-04-07 22:12:10.717 NSDictionary[5827:248322] add:  {    name0 = aaa;    name1 = eee;    name2 = ccc;    name3 = ddd;}2015-04-07 22:12:10.718 NSDictionary[5827:248322] 42015-04-07 22:12:10.718 NSDictionary[5827:248322] eee2015-04-07 22:12:10.718 NSDictionary[5827:248322] (null)2015-04-07 22:12:10.719 NSDictionary[5827:248322] ++++{    key0 = 123;    key1 = 456;    key2 = 678;    name0 = aaa;    name1 = eee;    name2 = ccc;    name3 = ddd;}2015-04-07 22:12:10.719 NSDictionary[5827:248322] ---{    key0 = 123;    key1 = 456;    key2 = 678;    name0 = aaa;    name2 = ccc;    name3 = ddd;}2015-04-07 22:12:10.719 NSDictionary[5827:248322] {}

运行结果分析