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

发布时间：2023-03-27 11:19:09 所属栏目：教程来源：

导读：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

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: removeObjectFo...

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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",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,}
2018-07-19 23:40:03.467838+0800 cyTest[67110:13778920] {3=chen6,6=chen6,}
2018-07-19 23:40:03.468030+0800 cyTest[67110:13778920] {3=chen6,}

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