NSPredicate，CoreData 中的空格。如何修剪谓词？
我有一个 CoreData/SQLite 应用程序，其中有“父类别”和“类别”。我无法控制数据，某些“父类别”值具有尾随空格。
我可以使用 CONTAINS （或者我应该说它可以与 CONTAINS 一起使用，但这是我无法使用的）。例如，我有 2 个条目：MEN 和 MENS。如果我使用 CONTAINS 我将返回两条记录，您可以看到这将是一个问题。
我可以轻松地在我这边进行修剪，但谓词会将其与数据库进行比较，并且不会匹配。所以我的问题是，如果可能的话，如何解释谓词中的空格。
我有一个类别“MENS”，有人在应用程序中选择了该类别，并将其与数据库中的“MENS”进行比较。
I have a CoreData/SQLite application in which I have "Parent Categories" and "Categories". I do not have control over the data, some of the "Parent Categories" values have trailing white spaces.
I could use CONTAINS (or I should say it works with CONTAINS but this is something I can not use). For example I have 2 entries, MEN and MENS. If I use CONTAINS I will return both records, you can see how this would be an issue.
I can easily trim on my side, but the predicate will compare that with the database and will not match. So my question is how can I account for whitespaces in the predicate, if possible at all.
I have a category "MENS" which someone has selected in the application, and it is compared against "MENS " in the database.
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我会在查找之前修剪数据。您可以使用
stringByTrimmingCharactersInSet轻松完成此操作。通过提前执行此操作，您还可以避免任何性能影响。如果您要与CONTAINS进行基于字符的比较，这可能会很昂贵。因此，假设您的搜索字符串是“MEN”。
以下是删除任何可疑字符的方法：
还有
whitespaceAndNewlineCharacterSet，它可以按照罐头上的说明执行操作。或者，您也可以轻松创建自己想要修剪的内容的自定义特征。
为此，请查看：
NSCharacterSet 类参考
和
Apple 的 字符串编程指南< /a>
I would trim the data prior to doing the lookup. You can do this easily using
stringByTrimmingCharactersInSet. By doing it beforehand, you'll also avoid any performance hit. That could be expensive if you're doing a character based comparison withCONTAINS.So, let's say your search string is "MEN".
Here's the way to strip out any dodgy characters:
There's also
whitespaceAndNewlineCharacterSetwhich does what it says on the tin.Alternatively, it's easy to create your own custom character of stuff you want to trim.
For that, have a look at:
NSCharacterSet Class Reference
and
Apple's String Programming Guide