Object-c 總結之NSDictionary

NSDictionary的常見用法總結

        NSArray *array1 = [NSArray arrayWithObjects:@"iphone",@"ipod",nil];

        NSArray *array2 = [NSArray arrayWithObjects:@"mac",@"imac",@"mac pro",nil];

        //類方法初始化自動釋放

        NSDictionary *myDictionary = [NSDictionary dictionaryWithObjectsAndKeys:array1,@"mobile",array2,@"computers",nil];//注意用nil結束

        NSLog(@"myDictionary = %@",myDictionary);

        

        int dictSize = [myDictionary count];

        //訪問字典中的值

        NSArray *mobile = [myDictionary objectForKey:@"mobile"];

        //從一個對象獲取鍵

        NSArray *keys = [myDictionary allKeysForObject:array1];

        //獲取字典中所有值得一個數組

        NSArray *values = [myDictionary allValues];

        //快速枚舉

        for(id key in myDictionary)

        {

            NSLog(@"key: %@,value: %@",key,[myDictionary objectForKey:key]);

        }

        //如果字典只包含屬性列表對象(NSData,NSDate,NSNumber,NSString,NSArray或NSDictionary)可以保存到文件中

        NSString *filePath = [[[NSBundlemainBundle]resourcePath]stringByAppendingPathComponent:@"dict.txt"];

        BOOL success = [myDictionary writeToFile:filePath atomically:YES];

        //用文件填充

        NSDictionary *myDict2 =[NSDictionary dictionaryWithContentsOfFile:filePath];

        

        //可變字典

        NSMutableDictionary *dictMutable = [[NSMutableDictionary alloc]initWithObjectsAndKeys:array1,@"mobile",array2,@"computer", nil];

        NSString *string4 = @"stringTV";

        //修改對象

        [dictMutable setObject:string4 forKey:@"media"];

        //刪除對象

        [dictMutable removeObjectForKey:@"mobile"];

        //刪除多個對象

        NSArray *keyArray =[NSArray arrayWithObjects:@"mobile",@"computer", nil];

        [dictMutable removeObjectForKey:keyArray];

        //刪除所有對象

        [dictMutable removeAllObjects];