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NSDictionary--字典
// // main.m // OC05-task-01 // // Created by Xin the Great on 15-1-25. // Copyright (c) 2015年 Xin the Great. All rights reserved. // #import <Foundation/Foundation.h> #import "NSArray+Log.h" int main(int argc, const char * argv[]) { @autoreleasepool { // insert code here... ////////////////NSDictionary--字典/////////////////// //初始化一个字典 //注意:字典里面所装数据类型:对象,不可以是基本数据类型 //字典是无序的 //key 通常是字符串, key必须唯一 NSDictionary *dic = [[NSDictionary alloc] initWithObjectsAndKeys: @"value",@"key", @"value1",@"key1", nil]; NSLog(@"dic is %@",dic); //创建一个数组 NSArray *names = @[@"张三", @"李四", @"王五"]; NSLog(@"names is %@", names); NSDictionary *dic2 = [NSDictionary dictionaryWithObjectsAndKeys: @"v1",@"k1", @"v2",@"k2", @"v3",@"k3", names,@"k4",nil]; NSLog(@"dic2 is %@", dic2); //从字典中取出value,如果这个字典不存在这个key, 则返回null NSString *str = [dic2 objectForKey:@"k1"]; NSLog(@"str is %@",str); NSArray *dArr = [dic2 objectForKey:@"k4"]; NSLog(@"dArr is %@", dArr); NSString *str1 = [dic2 objectForKey:@"k5"]; NSLog(@"str is %@",str1); //字典中键值对的个数 NSUInteger count = [dic2 count]; NSLog(@"count is %ld",count); //获取字典中所有的key NSArray *keys = [dic2 allKeys]; NSLog(@"keys is %@",keys); //获取所有的Value NSArray *values = [dic2 allValues]; NSLog(@"values is %@",values); //从字典中取出names的第一个元素 // NSArray *arr = [dic2 objectForKey:@"k4"]; // NSString *name1 = [arr objectAtIndex:0]; //嵌套调用 NSString *name1 = [[dic2 objectForKey:@"k4"] objectAtIndex:0]; NSLog(@"name1 is %@", name1); //字典的快速创建和取值方法 NSDictionary *dic3 = @{@"k1":@"v1", @"k2":@"v2", @"k3":@"v3"}; id str2 = dic3[@"k1"]; NSLog(@"str2 is %@",str2); } return 0; }
NSDictionary--字典
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