Searching through NSMutableArray of objects with NSPredicate

Question

The question is solved, here is how I fixed it for future reference for noobs like me I needed to remove the white-spaces: ship.countryOfbuild = [[elements objectAtIndex:0] stringByTrimmingCharactersInSet:[NSCharacterSet whitespaceAndNewlineCharacterSet]];

And I had to change the predicate like this: NSPredicate *resultPredicate = [NSPredicate predicateWithFormat:@"(countryOfBuild contains[cd] %@) OR (shipBuilder contains[cd] %@) OR (name contains[cd] %@) OR (owner contains[cd] %@)",searchText, searchText, searchText, searchText];

Original question

I'm using this tutorial to add a search bar to my project. I got the tableview all working, but the search function is crashing the app. The way I search now is:

-(void)filterContentForSearchText:(NSString*)searchText scope:(NSString*)scope
{
NSPredicate *resultPredicate = [NSPredicate
                                predicateWithFormat:@"SELF contains[cd] %@",
                                searchText];

searchResults = [searchContent filteredArrayUsingPredicate:resultPredicate];
}

The searchContentis a mutable array read from a .csv-file like this:

- (void)viewDidLoad
{
[super viewDidLoad];
NSString* pathToFile = [[NSBundle mainBundle] pathForResource:@"ships" ofType: @"csv"];

NSString *file = [[NSString alloc] initWithContentsOfFile:pathToFile encoding:  NSUTF8StringEncoding error:NULL];

NSArray *allLines = [file componentsSeparatedByCharactersInSet:[NSCharacterSet newlineCharacterSet]];


searchContent           = [[NSMutableArray alloc] init];


for (NSString* line in allLines) {
    NSArray *elements = [line componentsSeparatedByString:@";"];
    
    CargoShips* ship = [[CargoShips alloc]init];
    ship.countryOfbuild =  [elements objectAtIndex:0];
    ship.shipBuilder =     [elements objectAtIndex:1];
    ship.hullHashtag =     [elements objectAtIndex:2];
    ship.name =            [elements objectAtIndex:3];
    ship.owner =           [elements objectAtIndex:4];
    ship.shipOperator =    [elements objectAtIndex:5];
    ship.shipDelivery =    [elements objectAtIndex:6];
    ship.shipFlag =        [elements objectAtIndex:7];
    ship.shipClass =       [elements objectAtIndex:8];
    ship.powerPlant =      [elements objectAtIndex:9];
    ship.HP =              [elements objectAtIndex:10];
    ship.speed =           [elements objectAtIndex:11];
    ship.cargoSystem =     [elements objectAtIndex:12];
    ship.numberOfTanks =   [elements objectAtIndex:13];
    ship.size =            [elements objectAtIndex:14];
    [self.searchContent   addObject:ship];
}

I would like the search to search through all 15 pieces of the object (name, size, shipclass etc)

Currently, this crashes with the error:

*** Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: 'Can't use in/contains operator with collection <CargoShips: 0x714e1b0> (not a collection)'

CargoShips is my NSObject class.

How do I fix the NSPredicate to search through an NSMutableArraywith objects without crashing?

Here is the full code if that makes stuff easier http://pastebin.com/sw12GwHK

rdelmar rdelmar · Accepted Answer · 2013-01-31T16:06:07

You get this error because a ship is not a collection, so you can't use contains -- I think you need to search for a particular field in your ship object, and use LIKE not CONTAINS:

NSPredicate *resultPredicate = [NSPredicate predicateWithFormat:@"SELF.shipBuilder LIKE[cd] %@",searchText];

With LIKE you can use wild cards in the search. You could also use BEGINSWITH or ENDSWITH to search for the beginning or end of words.

Searching through NSMutableArray of objects with NSPredicate

3 Answers