IOS学习笔记二十一(NSDictionary、NSMutableDictionary)

1、NSDictionary、NSMutableDictionary

可以理解为java里面的map,一个key对应一个value，key不可以重复

NSDictionary不可变，NSMutableDictionary可变

NSMutableDictionary比NSDictionary多了一些增加，删除，修改的函数

比如setObject:forKey:  removeObjectForKey:


 
2、测试Demo

NSDictionary+print.h

    #import <Foundation/Foundation.h>
     
    
    #ifndef NSDictionary_print_h
    #define NSDictionary_print_h
    @interface NSDictionary (print)
    -(void)print;
    @end
     
     
    #endif /* NSDictionary_print_h */


NSDictionary+print.m

    #import <Foundation/Foundation.h>
    #import "NSDictionary+print.h"
     
    @implementation NSDictionary(print)
    -(void)print
    {
        NSMutableString *result = [NSMutableString stringWithFormat:@"{"];
        for (id key in self)
        {
            [result appendString:[key description]];
            [result appendString:@"="];
            [result appendString:[self[key] description]];
            [result appendString:@", "];
        }
        [result appendString:@"}"];
        NSLog(@"%@", result);
    }
    @end

 
main.m

    #import "NSDictionary+print.h"
     
    int main(int argc, char * argv[]) {
        @autoreleasepool {
            NSDictionary *dict = [NSDictionary dictionaryWithObjectsAndKeys:@"chenyu1", @"1", @"chenyu2", @"2", @"chenyu3", @"3", @"chenyu4", @"4", @"chenyu5", @"5",nil];
            [dict print];
            NSLog(@"dict有%ld个key-value", [dict count]);
            NSLog(@"key is 2 value is %@", [dict[@"2"] description]);
            NSLog(@"key is 2 value is %@", [dict objectForKey:@"2"]);
            NSLog(@"dict 所有的key是:%@", [dict allKeys]);
            NSEnumerator *en = [dict objectEnumerator];
            id obj;
            //遍历value
            while (obj = [en nextObject])
            {
                NSLog(@"%@", obj);
            }
            [dict enumerateKeysAndObjectsUsingBlock:^(id  _Nonnull key, id  _Nonnull obj, BOOL * _Nonnull stop) {
                NSLog(@"key的值为:%@", key);
                NSLog(@"value的值为:%@", obj);
            }];
            
            NSMutableDictionary *muDict = [NSMutableDictionary dictionaryWithObjectsAndKeys:@"chenyu1", @"1", @"chenyu2", @"2", @"chenyu3", @"3", @"chenyu4", @"4", @"chenyu5", @"5",nil];
            
            [muDict print];
            
            [muDict setObject:@"chen6" forKey:@"6"];
            [muDict setObject:@"chen6" forKey:@"3"];
            [muDict print];
            [muDict removeObjectForKey:@"1"];
            [muDict print];
      }
    }

3、运行结果

    2018-07-19 23:40:03.444261+0800 cyTest[67110:13778920] {3=chenyu3, 1=chenyu1, 4=chenyu4, 2=chenyu2, 5=chenyu5, }
    2018-07-19 23:40:03.446141+0800 cyTest[67110:13778920] dict有5个key-value
    2018-07-19 23:40:03.446320+0800 cyTest[67110:13778920] key is 2 value is chenyu2
    2018-07-19 23:40:03.446681+0800 cyTest[67110:13778920] key is 2 value is chenyu2
    2018-07-19 23:40:03.446972+0800 cyTest[67110:13778920] dict 所有的key是:(
        3,
        1,
        4,
        2,
        5
    )
    2018-07-19 23:40:03.447145+0800 cyTest[67110:13778920] chenyu3
    2018-07-19 23:40:03.447340+0800 cyTest[67110:13778920] chenyu1
    2018-07-19 23:40:03.447447+0800 cyTest[67110:13778920] chenyu4
    2018-07-19 23:40:03.447578+0800 cyTest[67110:13778920] chenyu2
    2018-07-19 23:40:03.447690+0800 cyTest[67110:13778920] chenyu5
    2018-07-19 23:40:03.448208+0800 cyTest[67110:13778920] key的值为:3
    2018-07-19 23:40:03.448322+0800 cyTest[67110:13778920] value的值为:chenyu3
    2018-07-19 23:40:03.448422+0800 cyTest[67110:13778920] key的值为:1
    2018-07-19 23:40:03.448515+0800 cyTest[67110:13778920] value的值为:chenyu1
    2018-07-19 23:40:03.448613+0800 cyTest[67110:13778920] key的值为:4
    2018-07-19 23:40:03.466511+0800 cyTest[67110:13778920] value的值为:chenyu4
    2018-07-19 23:40:03.466823+0800 cyTest[67110:13778920] key的值为:2
    2018-07-19 23:40:03.466983+0800 cyTest[67110:13778920] value的值为:chenyu2
    2018-07-19 23:40:03.467161+0800 cyTest[67110:13778920] key的值为:5
    2018-07-19 23:40:03.467334+0800 cyTest[67110:13778920] value的值为:chenyu5
    2018-07-19 23:40:03.467602+0800 cyTest[67110:13778920] {3=chenyu3, 1=chenyu1, 4=chenyu4, 2=chenyu2, 5=chenyu5, }
    2018-07-19 23:40:03.467838+0800 cyTest[67110:13778920] {3=chen6, 1=chenyu1, 6=chen6, 4=chenyu4, 2=chenyu2, 5=chenyu5, }
    2018-07-19 23:40:03.468030+0800 cyTest[67110:13778920] {3=chen6, 6=chen6, 4=chenyu4, 2=chenyu2, 5=chenyu5, }



 

作者：chen.yu
深信服三年半工作经验，目前就职游戏厂商，希望能和大家交流和学习,
微信公众号：编程入门到秃头 或扫描下面二维码
零基础入门进阶人工智能(链接)