我有一个NSMutableArray,它有一个内部NSMutableArray,我想通过内部NSMutableArray中的日期属性对其排序(对外部项进行排序)。
The array looks like this
[
{
messages : [
{
date
},
..... etc
]
},
..... etc
]
下面的代码是我抛出异常的尝试
NSSortDescriptor *sdSortDate = [NSSortDescriptor sortDescriptorWithKey:@"[email protected]" ascending:YES];
events = [NSMutableArray arrayWithArray:[events sortedArrayUsingDescriptors:@[sdSortDate]]];
例
*** Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: '[<__NSArrayM 0x604000654670> valueForKeyPath:]: this class does not implement the lastObject operation.'
有关如何做到这一点的任何想法?
你应该使用messages.date.@lastObject
而不是[email protected]
。请尝试下面的代码
NSSortDescriptor *sdSortDate = [NSSortDescriptor sortDescriptorWithKey:@"messages.date.@lastObject" ascending:YES];
events = [NSMutableArray arrayWithArray:[events sortedArrayUsingDescriptors:@[sdSortDate]]];