ios - 如何从 NSMutableArray 中删除 nil 对象？

Question

我的 NSMutableArray 包含以下数据

<DoctorInfo: 0x15de99e0> (entity: DoctorInfo; id: 0x15defbe0 <x-coredata://39D9B/DoctorInfo/p8> ; data: {
    doctorName = nil;
    emailAdd = nil;
    hospitalName = nil;
    mobileNumber = nil;
    phoneNumber = nil;
}),
<DoctorInfo: 0x15de9b00> (entity: DoctorInfo; id: 0x15da5dc0 <x-coredata://39D9BED3/DoctorInfo/p10> ; data: {
    doctorName = nil;
    emailAdd = nil;
    hospitalName = nil;
    mobileNumber = nil;
    phoneNumber = nil;
})
)

如何使用 nil 删除那些对象？我通过将 NSMutableArray 更改为 NSArray 尝试了以下代码，然后对其进行过滤，但它仍然无法正常工作:

 NSString *predString = [NSString stringWithFormat:@"(doctorName BEGINSWITH[cd] '%@')", nil];

    NSPredicate *pred = [NSPredicate predicateWithFormat:predString];

     self.filteredDocInfoArray = [self.unfilteredDocInfoArray filteredArrayUsingPredicate:pred];

Answer 1

像这样在谓词字符串中测试 nil:

NSPredicate *pred = [NSPredicate predicateWithFormat: @"doctorName = nil"];

参见 the documentation举些例子。