Objective-C 學習記錄6--dictionary

標籤：style   blog   color   使用   os   io   資料   for   

1.NSDictionary 和NSMutableDictionary

 

NSDictionary dictionaryWithObjectsAndKeys:~,nil

使用索引值對建立字典,用nil標誌結束

NSDictionary initWithObjectsAndKeys:

使用索引值對初始化字典,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];                  //快速枚舉遍曆所有KEY的值         for (NSObject *object in enumeratorKey) {             NSLog(@"遍曆KEY的值: %@",object);         }                  //得到詞典中所有Value值          NSEnumerator * enumeratorValue = [dictionary objectEnumerator];                  //快速枚舉遍曆所有Value的值         for (NSObject *object in enumeratorValue) {             NSLog(@"遍曆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;     } 

 

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

 

[NSMutableDictionary dictionaryWithCapacity:10];
//建立一個長度為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資料;[dictionary removeAllobjects];//刪除所有的資料;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                  //建立詞典對象，初始化長度為10         NSMutableDictionary *dictionary = [NSMutableDictionary dictionaryWithCapacity:10];                 //向詞典中動態添加資料         [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;     } 

 

 

[NSMutableDictionary dictionaryWithCapacity:10];
//建立一個長度為10的字典,不過字典的內容超過了10會自動增加.