NSPredicate数组内对象内的过滤器数组 [英] NSPredicate filter array within object within array

问题描述

我有以下方法：

- (NSMutableArray *)getFilteredArrayFromArray:(NSMutableArray *)array withText:(NSString *)text {

if ([array count] <= 0)
    return nil;

NSMutableArray *arrayToFilter = [NSMutableArray arrayWithArray:array];
NSString *nameformatString = [NSString stringWithFormat:@"stationName contains[c] '%@'", text];
NSPredicate *namePredicate = [NSPredicate predicateWithFormat:nameformatString];

NSString *descformatString = [NSString stringWithFormat:@"stationTagline contains[c] '%@'", text];
NSPredicate *descPredicate = [NSPredicate predicateWithFormat:descformatString];

NSString *aToZformatString = [NSString stringWithFormat:@"stationSearchData.browseAtozArray.city contains[c] '%@'", text];
NSPredicate *aToZPredicate = [NSPredicate predicateWithFormat:aToZformatString];

NSPredicate * combinePredicate = [NSCompoundPredicate orPredicateWithSubpredicates:[NSArray arrayWithObjects:namePredicate, descPredicate, aToZPredicate, nil]];

[arrayToFilter filterUsingPredicate:combinePredicate];

return arrayToFilter;
}

前2个谓词工作正常。但最后一个（aToZPredicate），是行不通的。 stationSearchData是一个StationSearchData对象，而browseAtozArray是一个NSMutableArray。

The first 2 predicates work fine. But the last one (aToZPredicate), is not working. stationSearchData is a StationSearchData object, and browseAtozArray is an NSMutableArray.

如何使用谓词基本上搜索数组中数组中的数组？

How can I use a predicate to essentially search an array within an array within an array?

这是StationSearchData对象的接口：

Here is the interface for the StationSearchData object:

@interface StationSearchData : NSObject

@property (nonatomic, strong) NSString *location;
@property (nonatomic, strong) NSString *city;
@property (nonatomic, strong) NSString *latitude;
@property (nonatomic, strong) NSString *longitude;

@property (nonatomic, strong) NSMutableArray *browseAtozArray;
@property (nonatomic, strong) NSMutableArray *genreArray;

@end

谢谢！

推荐答案

首先，你不应该使用 stringWithFormat 来构建谓词。如果搜索文本包含任何特殊字符，例如'或，则会导致
问题。
所以你应该替换

First of all, you should not use stringWithFormat to build predicates. This can cause problems if the search text contains any special characters like ' or ". So you should replace

NSString *nameformatString = [NSString stringWithFormat:@"stationName contains[c] '%@'", text];
NSPredicate *namePredicate = [NSPredicate predicateWithFormat:nameformatString];

by

NSPredicate *namePredicate = [NSPredicate predicateWithFormat:@"stationName contains[c] %@", text];

要在数组中搜索，必须在谓词中使用ANY：

To search within an array, you have to use "ANY" in the predicate:

NSPredicate *aToZPredicate =
  [NSPredicate predicateWithFormat:@"ANY stationSearchData.browseAtozArray.city CONTAINS[c] %@", text];

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