标签：style blog http io ar os sp for java
昨天学习了Foundation框架中NSArray类和NSMutableArray类：http://blog.csdn.net/jiangwei0910410003/article/details/41809719，今天来看一下Foundation框架中的NSDirctionary类，NSMutableDirctionary类，这个和Java中的Map类很想，OC中叫字典，Java中叫Map，还有字典是无序的，这个和NSArray不一样，Java中的Map也是无序的，通过hash值去检索元素的。
一、NSDirctionary类
//
// main.m
// 19_NSDictionary
//
// Created by jiangwei on 14-10-12.
// Copyright (c) 2014年 jiangwei. All rights reserved.
//
#import <Foundation/Foundation.h>
//由键值对key-value构成的数据集合
int main(int argc, const char * argv[]) {
@autoreleasepool {
//1.---------------------字典的创建
NSArray *array1 = [NSArray arrayWithObjects:@"zhangsan",@"zhangfei", nil];
NSArray *array2 = [NSArray arrayWithObjects:@"lisi",@"liping", nil];
//第一个元素:key:@"zhang" value:array1
//第二个元素:key:@"li" value:array2
NSDictionary *dict = [[NSDictionary alloc] initWithObjectsAndKeys:array1,@"zhang",array2,@"li", nil];
NSLog(@"%@",dict);
//存放一个元素
NSDictionary *dict2 = [NSDictionary dictionaryWithObject:array1 forKey:@"zhang"];
//2.---------------------获取所有的key
NSArray *allKeys = [dict allKeys];
//3.---------------------获取所有的value
//可能为二维数组
NSArray *allValues = [dict allValues];
//4.---------------------通过key获取value
NSArray *values = [dict objectForKey:@"zhang"];
//5.---------------------优化的语法
NSDictionary *dict3 = @{@"zhangsan":array1,@"lisi":array2};
NSLog(@"%@",dict3);
NSArray *array4 = dict3[@"zhang"];
}
return 0;
}
//1.---------------------字典的创建 NSArray *array1 = [NSArray arrayWithObjects:@"zhangsan",@"zhangfei", nil]; NSArray *array2 = [NSArray arrayWithObjects:@"lisi",@"liping", nil]; //第一个元素:key:@"zhang" value:array1 //第二个元素:key:@"li" value:array2 NSDictionary *dict = [[NSDictionary alloc] initWithObjectsAndKeys:array1,@"zhang",array2,@"li", nil]; NSLog(@"%@",dict);我们可以看到，NSDirctionary类的创建是基于NSArray的，然后其他的和Java中的Map就差不多了，一般是key-value的形式，当然这里也是需要注意结尾是：nil
运行结果：
打印结果是key-value的样式
2、添加元素
//存放一个元素 NSDictionary *dict2 = [NSDictionary dictionaryWithObject:array1 forKey:@"zhang"];
//2.---------------------获取所有的key NSArray *allKeys = [dict allKeys];
//3.---------------------获取所有的value //可能为二维数组 NSArray *allValues = [dict allValues];
//4.---------------------通过key获取value NSArray *values = [dict objectForKey:@"zhang"];
//5.---------------------优化的语法
NSDictionary *dict3 = @{@"zhangsan":array1,@"lisi":array2};
NSLog(@"%@",dict3);
NSArray *array4 = dict3[@"zhang"];二、NSMutableDirctionary类
//
// main.m
// 20_NSMutableDictionary
//
// Created by jiangwei on 14-10-12.
// Copyright (c) 2014年 jiangwei. All rights reserved.
//
#import <Foundation/Foundation.h>
//可变字典
int main(int argc, const char * argv[]) {
@autoreleasepool {
//1.-------------创建一个可变字典,大小为3
NSMutableDictionary *md1 = [[NSMutableDictionary alloc] initWithCapacity:3];
NSArray *array1 = [[NSArray alloc] initWithObjects:@"zhangsan",@"lis", nil];
//2.-------------添加元素
[md1 setObject:array1 forKey:@"zhang"];
NSMutableDictionary *md2 = [[NSMutableDictionary alloc] initWithCapacity:3];
[md2 addEntriesFromDictionary:md1];
//3.-------------删除元素
[md1 removeObjectForKey:@"zhang"];//以key删除
[md1 removeAllObjects];//删除所有元素
[md1 removeObjectsForKeys:array1];//以value删除
//4.-------------循环遍历字典
//快速遍历
for (NSString *key in md1) {
NSArray *values = [md1 objectForKey:key];
for(NSString *v in values){
NSLog(@"%@",v);
}
}
//普通遍历
NSArray *allKey = [md1 allKeys];
for(int i=0;i<allKey.count;i++){
NSArray *value = [md1 objectForKey:allKey[i]];
}
//字典是无序的
}
return 0;
}
之前的NSDirctionary类是不可变字典，同样的OC中也有对应的可变字典：NSMutableDirctionary1、创建可变字典
//1.-------------创建一个可变字典,大小为3 NSMutableDictionary *md1 = [[NSMutableDictionary alloc] initWithCapacity:3]; NSArray *array1 = [[NSArray alloc] initWithObjects:@"zhangsan",@"lis", nil];创建一个可变字典，可以指定其大小，当然当容量满的之后，他回自动扩容
2、添加元素
//2.-------------添加元素 [md1 setObject:array1 forKey:@"zhang"]; NSMutableDictionary *md2 = [[NSMutableDictionary alloc] initWithCapacity:3]; [md2 addEntriesFromDictionary:md1];
//3.-------------删除元素 [md1 removeObjectForKey:@"zhang"];//以key删除 [md1 removeAllObjects];//删除所有元素 [md1 removeObjectsForKeys:array1];//以value删除
//4.-------------循环遍历字典
//快速遍历
for (NSString *key in md1) {
NSArray *values = [md1 objectForKey:key];
for(NSString *v in values){
NSLog(@"%@",v);
}
}
//普通遍历
NSArray *allKey = [md1 allKeys];
for(int i=0;i<allKey.count;i++){
NSArray *value = [md1 objectForKey:allKey[i]];
}这一篇文章就介绍了OC中的NSDirctionary类和NSMutableDirctionary类，他们的用途在后面非常关键，经常被用到。
OC学习篇之---Foundation框架中的NSDirctionary类以及NSMutableDirctionary类
标签：style blog http io ar os sp for java
原文地址：http://blog.csdn.net/jiangwei0910410003/article/details/41830179
