字典的练习和使用（遍历，搜索。。。）（Student和Book类文件可以查看上篇博客这次不上传了。）

 

////  main.m//  NSDictionary////  Created by WildCat on 13-7-26.//  Copyright (c) 2013年 wildcat. All rights reserved.//#pragma mark - NSDictionary练习#import 
    
     #import "Student.h"#pragma  mark 创建字典void dictCreat(){    //第一种方式    NSDictionary *dict=[NSDictionary dictionaryWithObjectsAndKeys:                        @"v1",@"k1",                        @"v2",@"k2",                        @"v3",@"k3",nil];    NSLog(@"The Dictionary is:%@",dict);    //第二种方式    NSArray *objects=[NSArray arrayWithObjects:@"v1",@"v2",@"v3",@"v4", nil];    NSArray *keys=[NSArray arrayWithObjects:@"k1",@"k2",@"k3",@"k4", nil];    dict=[NSDictionary dictionaryWithObjects:objects forKeys:keys];    NSLog(@"The Dictionary is:%@",dict);}#pragma  mark 字典的使用void dictUser(){    //创建一个字典    NSDictionary *dict=[NSDictionary dictionaryWithObjectsAndKeys:                        @"v1",@"k1",                        @"v2",@"k2",                        @"v3",@"k3",nil];        //由于NSDIctionary是不可变的，只能取值，不能修改值    id obj=[dict objectForKey:@"k2"];//查找值    NSLog(@"The obj is :%@",obj);    NSInteger count=[dict count];//获得个数    NSLog(@"Count :%zi",count);        //将字典写入文件中    NSString *path=@"/Users/bird/Desktop/dict.xml";    [dict writeToFile:path atomically:YES];    //通过keys获得values    NSArray *objects=[dict objectsForKeys:[NSArray arrayWithObjects:@"k1",@"k2",@"k4", nil] notFoundMarker:@"not-finde"];    NSLog(@"object:%@",objects);}#pragma  mark 遍历字典void dictionaryFor(){    NSDictionary *dict=[NSDictionary dictionaryWithObjectsAndKeys:                        @"v1",@"k1",                        @"v2",@"k2",                        @"v3",@"k3",nil];    //第一种方法    for (id keys in dict) {        id object=[dict objectForKey:keys];        NSLog(@"%@--%@",keys,object);    }    //第二种方法  通过迭代器遍历    NSEnumerator *keyenu=[dict keyEnumerator];    id key=nil;    NSLog(@"迭代器遍历：");    while (key=[keyenu nextObject]) {        id object=[dict objectForKey:key];        NSLog(@"%@--%@",key,object);    }    NSLog(@"通过BLock遍历：");     //第二种方法  通过Block遍历    [dict enumerateKeysAndObjectsUsingBlock:^(id key, id obj, BOOL *stop) {        NSLog(@"%@--%@",key,obj);    }];    }#pragma mark 可变字典void mutableDictUser(){    Student *stu1=[Student initWithFirstName:@"lele" LastName:@"li"];    Student *stu2=[Student initWithFirstName:@"ll" LastName:@"li"];    Student *stu3=[Student initWithFirstName:@"xingle" LastName:@"li"];    NSMutableDictionary *dict=[NSMutableDictionary dictionary];    [dict setValue:stu1 forKey:@"k1"];    [dict setValue:stu2 forKey:@"k2"];    [dict setValue:stu3 forKey:@"k3"];    NSLog(@"%@",dict);    //删除所有元素    //[dict removeAllObjects];    //通过键值删除元素    [dict removeObjectForKey:@"k2"];    NSLog(@"%@",dict);}int main(int argc, const char * argv[]){    @autoreleasepool {                //dictCreat();        //dictUser();                //dictionaryFor();//遍历字典        mutableDictUser();            }    return 0;}