NSDictionary--字典

////  main.m//  OC05-task-01////  Created by Xin the Great on 15-1-25.//  Copyright (c) 2015年 Xin the Great. All rights reserved.//#import <Foundation/Foundation.h>#import "NSArray+Log.h"int main(int argc, const char * argv[]) {    @autoreleasepool {        // insert code here...        ////////////////NSDictionary--字典///////////////////                //初始化一个字典        //注意：字典里面所装数据类型：对象，不可以是基本数据类型        //字典是无序的        //key 通常是字符串， key必须唯一        NSDictionary *dic = [[NSDictionary alloc] initWithObjectsAndKeys:                             @"value",@"key",                             @"value1",@"key1", nil];                NSLog(@"dic is %@",dic);                //创建一个数组        NSArray *names = @[@"张三", @"李四", @"王五"];                NSLog(@"names is %@", names);        NSDictionary *dic2 = [NSDictionary dictionaryWithObjectsAndKeys:                              @"v1",@"k1",                              @"v2",@"k2",                              @"v3",@"k3",                              names,@"k4",nil];        NSLog(@"dic2 is %@", dic2);                //从字典中取出value,如果这个字典不存在这个key， 则返回null        NSString *str = [dic2 objectForKey:@"k1"];        NSLog(@"str is %@",str);        NSArray *dArr = [dic2 objectForKey:@"k4"];        NSLog(@"dArr is %@", dArr);        NSString *str1 = [dic2 objectForKey:@"k5"];        NSLog(@"str is %@",str1);                        //字典中键值对的个数        NSUInteger count = [dic2 count];        NSLog(@"count is %ld",count);                //获取字典中所有的key        NSArray *keys = [dic2 allKeys];        NSLog(@"keys is %@",keys);                //获取所有的Value        NSArray *values = [dic2 allValues];        NSLog(@"values is %@",values);        //从字典中取出names的第一个元素//        NSArray *arr = [dic2 objectForKey:@"k4"];//        NSString *name1 = [arr objectAtIndex:0];        //嵌套调用        NSString *name1 = [[dic2 objectForKey:@"k4"] objectAtIndex:0];        NSLog(@"name1 is %@", name1);                        //字典的快速创建和取值方法        NSDictionary *dic3 = @{@"k1":@"v1",                               @"k2":@"v2",                               @"k3":@"v3"};        id str2 = dic3[@"k1"];        NSLog(@"str2 is %@",str2);                    }    return 0;}