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, }
