Objective-C 学习记录6--dictionary

悠悠 2022-04-23 00:18 168阅读 0赞

# [Objective-C 学习记录6--dictionary][Objective-C _6--dictionary] #

1.NSDictionary 和NSMutableDictionary

NSDictionary dictionaryWithObjectsAndKeys:~,nil

使用键值对创建字典,用nil标志结束

NSDictionary initWithObjectsAndKeys:

使用键值对初始化字典,也用nil来表示结束.

dictionary count  计算其字典的长度.

dictionary keyEunmerator  将key全部存在NSEunmerator中,可以快速枚举其中的key的值.

dictionary objectForKey: key  通过key来查询值.

demo:

#import <UIKit/UIKit.h> 
        #import "MyClass.h" 
        int main(int argc, char *argv[]) 
        { 
            NSAutoreleasePool *pool = [[NSAutoreleasePool alloc] init]; 
           
            //添加我们的测试代码 
             
            NSDictionary *dictionary = [NSDictionary dictionaryWithObjectsAndKeys:@"我是值",@"我是key1",@"我是值2",@"我是key2", nil]; 
             
            //得到词典的数量 
            int count = [dictionary count]; 
            NSLog(@"词典的数量为： %d",count); 
             
            //得到词典中所有KEY值 
            NSEnumerator * enumeratorKey = [dictionary keyEnumerator]; 
             
            //快速枚举遍历所有KEY的值 
            for (NSObject *object in enumeratorKey) { 
                NSLog(@"遍历KEY的值: %@",object); 
            } 
             
            //得到词典中所有Value值 
             NSEnumerator * enumeratorValue = [dictionary objectEnumerator]; 
             
            //快速枚举遍历所有Value的值 
            for (NSObject *object in enumeratorValue) { 
                NSLog(@"遍历Value的值: %@",object); 
            } 
             
            //通过KEY找到value 
            NSObject *object = [dictionary objectForKey:@"我是key2"]; 
             
            if (object != nil) { 
                NSLog(@"通过KEY找到的value是: %@",object); 
            } 
             
             
             
            int retVal = UIApplicationMain(argc, argv, nil, nil); 
            [pool release]; 
            return retVal; 
        }

2.NSMutableDictionary是NSDictionary的子类,因此也继承其有的方法.

[NSMutableDictionary dictionaryWithCapacity:10];
    //创建一个长度为10的字典,不过字典的内容超过了10会自动增加.

[NSMutableDictionary initWithCapacity: 10];
    //初始化长度为10;
    
    
    [dictionary setObject:~ forKey;~];
    //x向可变的字典中添加数据;
    
    [dictionary removeAllobjects];//删除所有的数据;
    
    removeObjectForKey: //删除key的对应值;

#import <UIKit/UIKit.h> 
        #import "MyClass.h" 
        int main(int argc, char *argv[]) 
        { 
            NSAutoreleasePool *pool = [[NSAutoreleasePool alloc] init]; 
           
            //添加我们的测试代码 
             
            //创建词典对象，初始化长度为10 
            NSMutableDictionary *dictionary = [NSMutableDictionary dictionaryWithCapacity:10]; 
            
            //向词典中动态添加数据 
            [dictionary setObject:@"被添加的value1" forKey:@"key1"]; 
             
            [dictionary setObject:@"被添加的value2" forKey:@"key2"]; 
             
             
            //通过KEY找到value 
            NSObject *object = [dictionary objectForKey:@"key2"]; 
             
            if (object != nil) { 
                NSLog(@"通过KEY找到的value是: %@",object); 
            } 
             
             
             
            int retVal = UIApplicationMain(argc, argv, nil, nil); 
            [pool release]; 
            return retVal; 
        }

[NSMutableDictionary dictionaryWithCapacity:10];
    //创建一个长度为10的字典,不过字典的内容超过了10会自动增加.

posted @ 2014-08-13 17:16 [Rikies][] 阅读( ...) 评论( ...) [编辑][Link 1] 收藏

[Objective-C _6--dictionary]: https://www.cnblogs.com/ievjai/p/3910621.html
[Rikies]: https://www.cnblogs.com/ievjai/
[Link 1]: https://i.cnblogs.com/EditPosts.aspx?postid=3910621