OC语法--字典类

朴灿烈づ我的快乐病毒、 2022-06-18 03:47 195阅读 0赞

\#pragma mark 创建字典

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1.  void dictCreate() \{   
    
2.      //NSDictionary是不可变的  
    
3.      NSDictionary \*dict = \[NSDictionary dictionaryWithObject:@"v" forKey:@"k"\];  
    
4.      //最常用的初始化方式  
    
5.      dict = \[NSDictionary dictionaryWithObjectsAndKeys:  
    
6.              @"v1",@"k1",  
    
7.              @"v2",@"k2",  
    
8.              @"v3",@"k3",  
    
9.              nil\];  
    
10.     NSArray \*objs = \[NSArray arrayWithObjects:@"v1",@"v2",@"v3",nil\];  
    
11.     NSArray \*keys = \[NSArray arrayWithObjects:@"k2",@"k3",@"k4",nil\];  
    
12.     dict = \[NSDictionary dictionaryWithObjects:objs forKeys:keys\];  
    
13.       
    
14.     NSLog(@"%@",dict);  
    
15. \}

将字典写入文件，从文件读取：

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1.  void dicUse()\{   
    
2.      //NSDictionary是不可变的  
    
3.      NSDictionary \*dict = \[NSDictionary dictionaryWithObject:@"v" forKey:@"k"\];  
    
4.      //最常用的初始化方式  
    
5.      dict = \[NSDictionary dictionaryWithObjectsAndKeys:  
    
6.              @"v1",@"k0",  
    
7.              @"v2",@"k2",  
    
8.              @"v3",@"k3",  
    
9.              nil\];  
    
10.     //返回字典键值对  
    
11.     NSLog(@"count=%zi",dict.count);  
    
12.       
    
13.     //dictionary不可变，所以只能取值，不能修改  
    
14.     id obj = \[dict objectForKey:@"k3"\];  
    
15.     NSLog(@"obj=%@",obj);  
    
16.     NSLog(@"%@",dict);  
    
17.       
    
18.     //将字典写入文件  
    
19.     NSString \*path = @"/Users/luteresa/Desktop/dic.txt";  
    
20.     //\[dict writeToFile:path atomically:YES\];  
    
21.     dict = \[NSDictionary dictionaryWithContentsOfFile:path\];  
    
22.     NSLog(@"-%@",dict);  
    
23. \}

获取多个字典值：

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1.  void dictUse2()\{   
    
2.      //NSDictionary是不可变的  
    
3.      NSDictionary \*dict = \[NSDictionary dictionaryWithObject:@"v" forKey:@"k"\];  
    
4.      //最常用的初始化方式  
    
5.      dict = \[NSDictionary dictionaryWithObjectsAndKeys:  
    
6.              @"v1",@"k0",  
    
7.              @"v1",@"k2",  
    
8.              @"v3",@"k3",  
    
9.              nil\];  
    
10.     //返回字典键值对  
    
11.     NSLog(@"count=%zi",dict.count);  
    
12.       
    
13.     //返回所有的key  
    
14.     NSArray \*keys = \[dict allKeys\];  
    
15.     NSLog(@"keys=%@",keys);  
    
16.       
    
17.     //返回所有的value  
    
18.     NSArray \*objs = \[dict allValues\];  
    
19.     NSLog(@"%@",objs);  
    
20.     keys =\[dict allKeysForObject:@"v1"\];  
    
21.     NSLog(@"keys=%@",keys);
22.       
    
23.     //根据多个key取出对应的多个value  
    
24.     //当key找不到value时，用marker代替  
    
25.     objs = \[dict objectsForKeys: \[NSArray arrayWithObjects:@"k1",@"k2",nil\] notFoundMarker:@"h"\];  
    
26.     NSLog(@"%@",objs);  
    
27.       
    
28. \}

遍历字典：

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1.  void dicFor()\{   
    
2.      //NSDictionary是不可变的  
    
3.      NSDictionary \*dict = \[NSDictionary dictionaryWithObject:@"v" forKey:@"k"\];  
    
4.      //最常用的初始化方式  
    
5.      dict = \[NSDictionary dictionaryWithObjectsAndKeys:  
    
6.              @"v1",@"k0",  
    
7.              @"v1",@"k2",  
    
8.              @"v3",@"k3",  
    
9.              nil\];  
    
10.       
    
11.     for (id key in dict) \{   
    
12.         id value = \[dict objectForKey:key\];  
    
13.         NSLog(@"%@->%@",key,value);  
    
14.     \}  
    
15. \}

用key迭代器遍历字典：

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1.  void dicFor2()\{   
    
2.      //NSDictionary是不可变的  
    
3.      NSDictionary \*dict = \[NSDictionary dictionaryWithObject:@"v" forKey:@"k"\];  
    
4.      //最常用的初始化方式  
    
5.      dict = \[NSDictionary dictionaryWithObjectsAndKeys:  
    
6.              @"v1",@"k0",  
    
7.              @"v1",@"k2",  
    
8.              @"v3",@"k3",  
    
9.              nil\];  
    
10.     //key 迭代器  
    
11.     NSEnumerator \*enumerator = \[dict keyEnumerator\];  
    
12.     id key = nil;  
    
13.     while (key = \[enumerator nextObject\]) \{   
    
14.         id value = \[dict objectForKey:key\];  
    
15.         NSLog(@"%@->%@",key,value);  
    
16.     \}  
    
17.     //  
    
18. \}

用block迭代

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1.  void dicFor3()\{   
    
2.      //NSDictionary是不可变的  
    
3.      NSDictionary \*dict = \[NSDictionary dictionaryWithObject:@"v" forKey:@"k"\];  
    
4.      //最常用的初始化方式  
    
5.      dict = \[NSDictionary dictionaryWithObjectsAndKeys:  
    
6.              @"v1",@"k0",  
    
7.              @"v1",@"k2",  
    
8.              @"v3",@"k3",  
    
9.              nil\];  
    
10.     \[dict enumerateKeysAndObjectsUsingBlock:^(id key, id obj, BOOL \*stop) \{   
    
11.         NSLog(@"%@=%@",key,obj);  
    
12.     \}\];  
    
13.       
    
14.     
    
15. \}

NSMutableDictionary:字典子集，可变

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1.  void dicMutUse()\{   
    
2.      NSMutableDictionary \*dict = \[NSMutableDictionary dictionary\];  
    
3.      Student \*stu1 = \[Student studentWithName:@"name1"\];  
    
4.      Student \*stu2 = \[Student studentWithName:@"name2"\];  
    
5.        
    
6.      \[dict setObject:stu1 forKey:@"k1"\];  
    
7.      \[dict setObject:stu2 forKey:@"k2"\];  
    
8.      NSLog(@"retain:%zi",\[stu1 retainCount\]);  
    
9.    
    
10.     NSLog(@"%@->%@",@"k1",\[\[dict objectForKey:@"k1"\] name\]);  
    
11.     //\[dict removeAllObjects\];  
    
12.     //\[dict removeObjectForKey:@"k1"\];  
    
13.     NSLog(@"retain:%zi",\[stu1 retainCount\]);  
    
14.    // NSLog(@"%@",stu1);  
    
15.       
    
16.     //添加其他字典  
    
17.     NSDictionary \*other = \[NSDictionary dictionaryWithObject:@"name3" forKey:@"k3"\];  
    
18.     \[dict addEntriesFromDictionary:other\];  
    
19.     NSLog(@"count is %zi",\[dict count\]);  
    
20.       
    
21.     //NSLog(@"%@->%@",@"k3",\[dict objectForKey:@"k3"\]);  
22. \}

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