NSMutableDictionary--可变字典

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//
//  main.m
//  OC05-task-02
//
//  Created by Xin the Great on 15-1-25.
//  Copyright (c) 2015年 Xin the Great. All rights reserved.
//

#import <Foundation/Foundation.h>

int main(int argc, const char * argv[]) {
    @autoreleasepool {
        // insert code here...
        ///////////////NSMutableDictionary--可变字典///////////////
        
        //初始化可变字典
        //空的字典
        NSMutableDictionary *dic1 = [NSMutableDictionary dictionary];
        NSLog(@"dic1 is %@", dic1);
        
        //给字典预期的一个空间
        NSMutableDictionary *dic2 = [NSMutableDictionary dictionaryWithCapacity:10];
        
        //添加元素
        [dic1 setObject:@"value1" forKey:@"key1"];
        [dic1 setObject:@"value2" forKey:@"key2"];
        [dic1 setObject:@"value3" forKey:@"key3"];
        
        //设置键值对，如果key已经存在，则是修改key所对应的value， 如果不存在，则创建一个新的键值对
        [dic1 setObject:@"value4" forKey:@"key4"];

        NSLog(@"dic1 is %@", dic1);
        
        
        //删除元素
        //删除指定的元素
        [dic1 removeObjectForKey:@"key2"];
        NSLog(@"dic1 is %@", dic1);

        //删除所有的元素
        [dic1 removeAllObjects];
        NSLog(@"dic1 is %@", dic1);


        //字典的遍历
        NSDictionary *dic = @{@"k1":@"v1",
                              @"k2":@"v2",
                              @"k3":@"v3",
                              @"k4":@"v4",
                              @"k5":@"v5",};
        
        //传统遍历

        NSArray *keys = [dic allKeys];
        
        for (int i = 0; i < dic.count; i++) {
            //获取key
            NSString *key = keys[i];
            NSString *value = dic[key];
            NSLog(@"value[%@] is %@", key, value);
        }
        
        NSLog(@"------------------------------");
        
        //快速遍历, 快速遍历效率要高于传统遍历
        for (NSString *key in dic) {
            NSString *value = dic[key];
            NSLog(@"value[%@] is %@", key, value);
        }
        
        
        
        
    }
    return 0;
}

NSMutableDictionary--可变字典

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原文地址：http://blog.csdn.net/zuojx1013/article/details/43163737