昨天学习了Foundation框架中NSArray类和NSMutableArray类：http://blog.csdn.net/jiangwei0910410003/article/details/41809719，今天来看一下Foundation框架中的NSDirctionary类，NSMutableDirctionary类，这个和Java中的Map类很想，OC中叫字典，Java中叫Map，还有字典是无序的，这个和NSArray不一样，Java中的Map也是无序的，通过hash值去检索元素的。

一、NSDirctionary类

//
//  main.m
//  19_NSDictionary
//
//  Created by jiangwei on 14-10-12.
//  Copyright (c) 2014年 jiangwei. All rights reserved.
//

#import <Foundation/Foundation.h>

//由键值对key-value构成的数据集合
int main(int argc, const char * argv[]) {
    @autoreleasepool {
        //1.---------------------字典的创建
        NSArray *array1 = [NSArray arrayWithObjects:@"zhangsan",@"zhangfei", nil];
        NSArray *array2 = [NSArray arrayWithObjects:@"lisi",@"liping", nil];
        
        //第一个元素:key:@"zhang" value:array1
        //第二个元素:key:@"li"  value:array2
        NSDictionary *dict = [[NSDictionary alloc] initWithObjectsAndKeys:array1,@"zhang",array2,@"li", nil];
        NSLog(@"%@",dict);
        
        //存放一个元素
        NSDictionary *dict2 = [NSDictionary dictionaryWithObject:array1 forKey:@"zhang"];
        
        
        //2.---------------------获取所有的key
        NSArray *allKeys = [dict allKeys];
        
        
        //3.---------------------获取所有的value
        //可能为二维数组
        NSArray *allValues = [dict allValues];
        
        
        //4.---------------------通过key获取value
        NSArray *values = [dict objectForKey:@"zhang"];
        
        
        //5.---------------------优化的语法
        NSDictionary *dict3 = @{@"zhangsan":array1,@"lisi":array2};
        NSLog(@"%@",dict3);
        
        NSArray *array4 = dict3[@"zhang"];
        
        
    }
    return 0;
}

//1.---------------------字典的创建
NSArray *array1 = [NSArray arrayWithObjects:@"zhangsan",@"zhangfei", nil];
NSArray *array2 = [NSArray arrayWithObjects:@"lisi",@"liping", nil];

//第一个元素:key:@"zhang" value:array1
//第二个元素:key:@"li"  value:array2
NSDictionary *dict = [[NSDictionary alloc] initWithObjectsAndKeys:array1,@"zhang",array2,@"li", nil];
NSLog(@"%@",dict);

运行结果：

打印结果是key-value的样式

2、添加元素

//存放一个元素
NSDictionary *dict2 = [NSDictionary dictionaryWithObject:array1 forKey:@"zhang"];

//2.---------------------获取所有的key
NSArray *allKeys = [dict allKeys];

//3.---------------------获取所有的value
//可能为二维数组
NSArray *allValues = [dict allValues];

//4.---------------------通过key获取value
NSArray *values = [dict objectForKey:@"zhang"];

//5.---------------------优化的语法
NSDictionary *dict3 = @{@"zhangsan":array1,@"lisi":array2};
NSLog(@"%@",dict3);

NSArray *array4 = dict3[@"zhang"];

二、NSMutableDirctionary类

//
//  main.m
//  20_NSMutableDictionary
//
//  Created by jiangwei on 14-10-12.
//  Copyright (c) 2014年 jiangwei. All rights reserved.
//

#import <Foundation/Foundation.h>

//可变字典
int main(int argc, const char * argv[]) {
    @autoreleasepool {
        //1.-------------创建一个可变字典,大小为3
        NSMutableDictionary *md1 = [[NSMutableDictionary alloc] initWithCapacity:3];
        NSArray *array1 = [[NSArray alloc] initWithObjects:@"zhangsan",@"lis", nil];
        
        
        //2.-------------添加元素
        [md1 setObject:array1 forKey:@"zhang"];
        
        NSMutableDictionary *md2 = [[NSMutableDictionary alloc] initWithCapacity:3];
        [md2 addEntriesFromDictionary:md1];
        
        
        //3.-------------删除元素
        [md1 removeObjectForKey:@"zhang"];//以key删除
        [md1 removeAllObjects];//删除所有元素
        [md1 removeObjectsForKeys:array1];//以value删除
        
        
        //4.-------------循环遍历字典
        //快速遍历
        for (NSString *key in md1) {
            NSArray *values = [md1 objectForKey:key];
            for(NSString *v in values){
                NSLog(@"%@",v);
            }
        }
        
        //普通遍历
        NSArray *allKey = [md1 allKeys];
        for(int i=0;i<allKey.count;i++){
            NSArray *value = http://www.mamicode.com/[md1 objectForKey:allKey[i]];>之前的NSDirctionary类是不可变字典，同样的OC中也有对应的可变字典：NSMutableDirctionary
1、创建可变字典
//1.-------------创建一个可变字典,大小为3
NSMutableDictionary *md1 = [[NSMutableDictionary alloc] initWithCapacity:3];
NSArray *array1 = [[NSArray alloc] initWithObjects:@"zhangsan",@"lis", nil];
创建一个可变字典，可以指定其大小，当然当容量满的之后，他回自动扩容

2、添加元素
//2.-------------添加元素
[md1 setObject:array1 forKey:@"zhang"];

NSMutableDictionary *md2 = [[NSMutableDictionary alloc] initWithCapacity:3];
[md2 addEntriesFromDictionary:md1];

3、删除元素
//3.-------------删除元素
[md1 removeObjectForKey:@"zhang"];//以key删除
[md1 removeAllObjects];//删除所有元素
[md1 removeObjectsForKeys:array1];//以value删除

4、遍历字典
//4.-------------循环遍历字典
//快速遍历
for (NSString *key in md1) {
    NSArray *values = [md1 objectForKey:key];
    for(NSString *v in values){
        NSLog(@"%@",v);
    }
}

//普通遍历
NSArray *allKey = [md1 allKeys];
for(int i=0;i<allKey.count;i++){
    NSArray *value = http://www.mamicode.com/[md1 objectForKey:allKey[i]];>

总结
这一篇文章就介绍了OC中的NSDirctionary类和NSMutableDirctionary类，他们的用途在后面非常关键，经常被用到。





OC学习篇之---Foundation框架中的NSDirctionary类以及NSMutableDirctionary类