Question

如何使用NSPredicate过滤数组中的对象 - ＆gt; _title变量等于变量title？我尝试了以下内容，但它没有过滤任何内容。

NSMutableArray *array = [[posts mutableCopy] autorelease];
NSString *title = [[TBForrstr sharedForrstr] stringForPostType:type];
[array filterUsingPredicate:[NSPredicate predicateWithFormat:[NSString stringWithFormat:@"SELF->_title == %@", title]]];

Answer 1

确保标题与数组完全匹配。或者，如果您想要更灵活，请将其设置为不区分大小写：

NSMutableArray *array = [[posts mutableCopy] autorelease];
NSString *title = [[TBForrstr sharedForrstr] stringForPostType:type];
[array filterUsingPredicate:[NSPredicate predicateWithFormat:@"_title == [cd]%@", title]];

Answer 2

这个对我有用 - 请注意字符串周围的单引号：

NSArray *posts = [NSArray arrayWithObjects:
    [NSDictionary dictionaryWithObjectsAndKeys: @"Cat or dog?", @"_title", nil],
    [NSDictionary dictionaryWithObjectsAndKeys: @"I saved a file, where is it?", @"_title", nil],
    [NSDictionary dictionaryWithObjectsAndKeys: @"How should I do this?", @"_title", nil],
nil];

NSMutableArray *array = [[posts mutableCopy] autorelease];
NSString *title = @"Cat or dog?";
[array filterUsingPredicate:[NSPredicate predicateWithFormat:[NSString stringWithFormat:@"SELF._title == '%@'", title]]];

NSLog(@"%@", array);

Answer 3

只需使用：

[NSPRedicate predicateWithFormat:@"title LIKE %@",title]

标题应通过KVC

与您的_title ivar相匹配

NSPredicate过滤器阵列

3 个答案: