使用NSPredicate过滤NSArray [英] Filter NSArray with NSPredicate

问题描述

我想过滤 User 对象的数组( User 具有 fullname ， user_id 和其他一些属性..)根据以某些字符串开头的 firstName 或 lastName .
我知道如何根据一种条件进行过滤:

I want to filter an array of User objects (User has fullname, user_id and some more attributes..) according to firstName or lastName that begin with some string.
I know how to filter according to one condition:

NSPredicate* predicate = [NSPredicate predicateWithFormat:@"firstName BEGINSWITH[cd] %@", word];
NSArray* resArr = [myArray filteredArrayUsingPredicate:predicate];  

这将给我所有具有以"word"开头的名字的用户.
但是，如果我希望所有具有以"word"开头的名字或姓氏的用户呢?

this will give me all the users that has a firstName that starts with "word".
But what if I want all the users that has a firstName or lastName that start with "word"?

推荐答案

您可以使用类 NSCompoundPredicate 创建复合谓词.

You can use the class NSCompoundPredicate to create compound predicates.

NSPredicate *firstNamePred = [NSPredicate predicateWithFormat:@"firstName BEGINSWITH[cd] %@", word];
NSPredicate *lastNamePred = [NSPredicate predicateWithFormat:@"lastName BEGINSWITH[cd] %@", word];

NSArray *predicates = @[firstNamePred, lastNamePred];

NSPredicate *compoundPredicate = [NSCompoundPredicate orPredicateWithSubpredicates:predicates];

NSArray* resArr = [myArray filteredArrayUsingPredicate:compoundPredicate];

这是我喜欢的一种方式.

this is one way that I like doing.

或者你可以做...

NSPredicate* predicate = [NSPredicate predicateWithFormat:@"firstName BEGINSWITH[cd] %@ OR lastName BEGINSWITH[cd] %@", word, word];
NSArray* resArr = [myArray filteredArrayUsingPredicate:predicate];

两者都将起作用.

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