CODEWITHSUNDEEP
iphoneobjective-cipadcore-datanspredicate
Kristof
Kristof

Reputation: 557

NSPredicate in NSFetchedResultsController acting strange

NSPredicate *predicate = [NSPredicate predicateWithFormat:@"List.name == 'kristof\\'s list'"];

Works as expected. However I want do something like this:

    NSString *listName = [[[detailItem valueForKey:@"name"] description] stringByReplacingOccurrencesOfString:@"'" withString:@"\\'"];
NSPredicate *predicate = [NSPredicate predicateWithFormat:@"List.name == '%@'", listName];

It returns nothing, even if I try this:

NSPredicate *predicate = [NSPredicate predicateWithFormat:@"List.name == '%@'", @"kristof\\'s list"];

It remains empty. Any ideas ?

Upvotes: 1

Views: 188

Answers (1)

lyonanderson
lyonanderson

Reputation: 2035

The behaviour of [NSString stringWithFormat] and [NSPredicate predicateWithFormat] are different. NSString performs the substitution on creation, whereas NSPredicate on evaluation. Your single quotes are preventing the substitution.

For more take a look at the CocoaDev Forums.

Upvotes: 2

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