1 倒序

NSMutableArray *uploadImageArray = [NSMutableArray new]  ;

uploadImageArray= (NSMutableArray*)[[uploadImageArray reverseObjectEnumerator]allObjects];

2 数组拷贝

NSMutableArray *mutableCopyArr = [searchArray mutableCopy];

3 判断数组内容是否已经存在（包含）

BOOL isbool = [mutableCopyArr containsObject: searchBar.text];

4 将数组中的内容拼接成字符串

NSString *string = [array componentsJoinedByString:@","];//   ,  分隔符

5 将字符串切割成数组

NSString*a = [[NSStringalloc]initWithString:@"冬瓜，西瓜，火龙果，大头，小狗"];

NSArray *b = [a componentsSeparatedByString:@"，"];

NSString*a3 = [bobjectAtIndex:2];