Coredata：在谓词和比较中将NSString列转换为NSDate [英] Coredata: Convert NSString column to NSDate in predicate and Compare

问题描述

您好我正在开发一个IOS应用程序。其中日期以String列的形式存储在核心数据实体中。现在我想根据日期得到一些过滤的记录。但是问题是日期被保存为String而不是coredata中的NSDate对象。

Hi I am developing an IOS application. In which the dates are stored in String column type in core data entity. Now I want to get some filtered records based on date. But the problem is that the date is saved as String not as NSDate object in coredata.

我的问题是有一种方法来转换Nsdate中的字符串， NSDate对象并获取更大和更小的日期。我想在MYSQL查询中使用MySQL的DATE（）函数，并将字符串转换为Date并与任何日期进行比较。

My Question is that is there a way to convert String in Nsdate and compare it with the NSDate object and get the greater and smaller dates. I want something like in MYSQL query where you can use "DATE()" function of MySQL and convert a String to Date and compare it with any date.

推荐答案

我想你可以通过在你的NSManagedObject子类创建一个类别，并创建一个函数，可以将你的nsstring日期转换为nsdate。然后你可以在NSPredicate中比较。

i think you can by creating a category on your NSManagedObject subclass and create a function that can convert your nsstring date into a nsdate . Then you could compare that in an NSPredicate.

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