NSDictionary

  1 //
  2 //  main.m
  3 //  NSDictionary
  4 //
  5 //  Created by dingxiaowei on 13-5-15.
  6 //  Copyright (c) 2013年 dingxiaowei. All rights reserved.
  7 //
  8
  9 #import <Foundation/Foundation.h>
 10 #import "Student.h"
 11 #pragma mark - 字典的创建
 12 void dicCreate(){
 13     //NSDictionary一旦创建是不可变的  可变的是NSMutableDictionary
 14     //创建一个键值对
 15     NSDictionary  *dic=[NSDictionary dictionaryWithObject:@"dingxiaowei" forKey:@"10141303"]; //只能放OC对象，不能放基本数据类型  注意：不能处理中文
 16     //创建多个键值对(最常用的初始化方法)
 17     dic=[NSDictionary dictionaryWithObjectsAndKeys:@"cl",@"10141301",
 18                                                    @"cey",@"10141302",
 19                                                    @"dxw",@"10141303", nil];
 20     //其他创建方法
 21     NSArray *objs=[NSArray arrayWithObjects:@"v1",@"v2",@"v3", nil];
 22     NSArray *keys=[NSArray arrayWithObjects:@"k1",@"k2",@"k3", nil];
 23     dic=[NSDictionary dictionaryWithObjects:objs forKeys:keys];
 24     NSLog(@"字典是：%@",dic);
 25 }
 26 #pragma mark - 字典的用法
 27 void dicUse(){
 28     //创建多个键值对(最常用的初始化方法)
 29     NSDictionary *dic=[NSDictionary dictionaryWithObjectsAndKeys:
 30                        @"v1",@"k1",
 31                        @"cey",@"10141302",
 32                        @"dxw",@"10141303", nil];
 33     NSLog(@"count:%zi",[dic count]);
 34     //由于NSDictionary是不可变的，所以一旦创建只能查询，不能更改
 35     id obj=[dic objectForKey:@"k1"];
 36     NSLog(@"k1-%@",obj);
 37
 38     //将字典写入文件中
 39     NSString *path=@"/Users/dingxiaowei/Desktop/dictionary.xml";
 40     if([dic writeToFile:path atomically:YES]){
 41         NSLog(@"字典写入到文件成功");
 42     }
 43     //读取xml的字典文件
 44     dic=[NSDictionary dictionaryWithContentsOfFile:path];
 45     NSLog(@"文件读取成功\ndic:%@",dic);
 46
 47     //返回所有的keys和values
 48     NSArray *keys=[dic allKeys];
 49     NSArray *values=[dic allValues];
 50     NSLog(@"所有的keys是：%@\n所有的值是：%@",keys,values);
 51
 52     //查询一个value对于的多个key
 53     dic=[NSDictionary dictionaryWithObjectsAndKeys:@"v1",@"k1",@"v2",@"k2",@"v1",@"k3",nil];
 54     keys=[dic allKeysForObject:@"v1"];
 55     NSLog(@"keys:%@",keys);
 56
 57     //根据多个key取出对于的value
 58     //注意：当key找不到对于的value时候，就用marker来代替
 59     NSArray *array1=[NSArray array];
 60     array1=[dic objectsForKeys:[NSArray arrayWithObjects:@"k1",@"k2", @"k4",nil] notFoundMarker:@"not-found"];//如果找不到对于的object 就用marker代替 比如这儿没有k4
 61     NSLog(@"找到的值%@",array1);
 62 }
 63 #pragma mark - 遍历字典
 64 void dicFor(){
 65     //初始化字典
 66     NSDictionary *dic=[NSDictionary dictionaryWithObjectsAndKeys:@"v1",@"k1",@"v2",@"k2",@"v3",@"k3", nil];
 67     //遍历字典所有的key
 68     for (id key in dic) {
 69         id value=[dic objectForKey:key];
 70         NSLog(@"普通遍历：%@-%@",key,value);
 71     }
 72
 73     //key迭代器遍历
 74     NSEnumerator *enumer=[dic keyEnumerator];
 75     id key=nil;
 76     while (key=[enumer nextObject]) {
 77         id value=[dic objectForKey:key];
 78         NSLog(@"key迭代器遍历：%@-%@",key,value);
 79     }
 80
 81     //value迭代器
 82     //对象迭代器
 83     //[dic objectEnumerator];
 84
 85     //lblock遍历(每调遍历一次键值就调用一次block
 86     [dic enumerateKeysAndObjectsUsingBlock:^(id key, id obj, BOOL *stop) {
 87         NSLog(@"block迭代器遍历：%@-%@",key,obj);
 88     }];
 89 }
 90 #pragma mark - 字典的内存管理
 91 void dicMemory(){
 92     Student *stu1=[Student studentWithName:@"cl"];
 93     Student *stu2=[Student studentWithName:@"cey"];
 94     Student *stu3=[Student studentWithName:@"dxw"];
 95     //字典会自动销毁，一般静态创建的对象都不需要我们自己释放，自动释放的时候会对key和value对象进行一次release操作
 96     NSDictionary *dic=[NSDictionary dictionaryWithObjectsAndKeys:stu1,@"k1",stu2,@"k2",stu3,@"k3",nil]; //注意：把一个对象塞给字典时会进行一次retain时候
 97     /*[stu1 retain];
 98     [stu2 retain];
 99     [stu3 retain];*/
100
101
102     NSLog(@"dic%@",dic);
103 }
104
105 int main(int argc, const char * argv[])
106 {
107
108     @autoreleasepool {
109
110         //dicCreate();
111         //dicUse();
112         //dicFor();
113         dicMemory();
114     }
115     return 0;
116 }

Student.h

1 #import <Foundation/Foundation.h>
2
3 @interface Student : NSObject
4 @property(nonatomic,retain)NSString *name;
5 +(id)studentWithName:(NSString *)name;
6 @end

Student.m

 1 #import "Student.h"
 2
 3 @implementation Student
 4
 5
 6 +(id)studentWithName:(NSString *)name{
 7     Student *stu=[[[Student alloc] init] autorelease];
 8     stu.name=name;
 9     return stu;
10 }
11
12 -(NSString *)description{
13     return _name;
14 }
15
16 -(void)dealloc{
17     NSLog(@"名字为%@被销毁了",_name);
18     [_name release];
19     [super dealloc];
20 }
21
22 @end