1.NSDictionary 和NSMutableDictionary

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NSDictionary dictionaryWithObjectsAndKeys:~,nil

使用鍵值對創建字典,用nil標志結束

NSDictionary initWithObjectsAndKeys:

使用鍵值對初始化字典,也用nil來表示結束.

dictionary count? 計算其字典的長度.

dictionary keyEunmerator? 將key全部存在NSEunmerator中,可以快速枚舉其中的key的值.

dictionary objectForKey: key? 通過key來查詢值.

demo:

#import <UIKit/UIKit.h> #import "MyClass.h" int main(int argc, char *argv[]) { NSAutoreleasePool *pool = [[NSAutoreleasePool alloc] init]; //添加我們的測試代碼 NSDictionary *dictionary = [NSDictionary dictionaryWithObjectsAndKeys:@"我是值",@"我是key1",@"我是值2",@"我是key2", nil]; //得到詞典的數量 int count = [dictionary count]; NSLog(@"詞典的數量為： %d",count); //得到詞典中所有KEY值 NSEnumerator * enumeratorKey = [dictionary keyEnumerator]; //快速枚舉遍歷所有KEY的值 for (NSObject *object in enumeratorKey) { NSLog(@"遍歷KEY的值: %@",object); } //得到詞典中所有Value值 NSEnumerator * enumeratorValue = [dictionary objectEnumerator]; //快速枚舉遍歷所有Value的值 for (NSObject *object in enumeratorValue) { NSLog(@"遍歷Value的值: %@",object); } //通過KEY找到value NSObject *object = [dictionary objectForKey:@"我是key2"]; if (object != nil) { NSLog(@"通過KEY找到的value是: %@",object); } int retVal = UIApplicationMain(argc, argv, nil, nil); [pool release]; return retVal; }

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2.NSMutableDictionary是NSDictionary的子類,因此也繼承其有的方法.

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[NSMutableDictionary dictionaryWithCapacity:10];
//創建一個長度為10的字典,不過字典的內容超過了10會自動增加.
[NSMutableDictionary initWithCapacity: 10]; //初始化長度為10; [dictionary setObject:~ forKey;~]; //x向可變的字典中添加數據; [dictionary removeAllobjects];//刪除所有的數據; removeObjectForKey: //刪除key的對應值; #import <UIKit/UIKit.h> #import "MyClass.h" int main(int argc, char *argv[]) { NSAutoreleasePool *pool = [[NSAutoreleasePool alloc] init]; //添加我們的測試代碼 //創建詞典對象，初始化長度為10 NSMutableDictionary *dictionary = [NSMutableDictionary dictionaryWithCapacity:10]; //向詞典中動態添加數據 [dictionary setObject:@"被添加的value1" forKey:@"key1"]; [dictionary setObject:@"被添加的value2" forKey:@"key2"]; //通過KEY找到value NSObject *object = [dictionary objectForKey:@"key2"]; if (object != nil) { NSLog(@"通過KEY找到的value是: %@",object); } int retVal = UIApplicationMain(argc, argv, nil, nil); [pool release]; return retVal; }

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[NSMutableDictionary dictionaryWithCapacity:10];
//創建一個長度為10的字典,不過字典的內容超過了10會自動增加.

轉載于:https://www.cnblogs.com/ievjai/p/3910621.html

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