CODEWITHSUNDEEP
objective-ciosnspredicate
mjisrawi
mjisrawi

Reputation: 7936

NSPredicate with multiple comparisons for one query string

I was wondering if there is a way to simplify an NSPredicate that takes in a single query string for multiple comparison targets. I'm searching multiple attributes of a core data entity for the same query string. My current query looks something like this...

[NSPredicate predicateWithFormat:@"(attributeA contains[cd] %@) OR (attributeB contains[cd] %@) OR (attributeC contains[cd] %@)", searchString, searchString, searchString];

Note that this works perfectly, but it does look a bit unsightly. Especially the searchString, searchString, searchString part. Any tips on how I could possibly simplify this would be great!

thanks!

Upvotes: 3

Views: 4035

Answers (2)

Onur Var
Onur Var

Reputation: 1808

You can use NSCompoundPredicate for your OR & AND operations like this.

Obj-C - OR

// OR Condition //

NSPredicate *predicate1 = [NSPredicate predicateWithFormat:@"X == 1"];
NSPredicate *predicate2 = [NSPredicate predicateWithFormat:@"X == 2"];
NSPredicate *predicate = [NSCompoundPredicate orPredicateWithSubpredicates:@[predicate1, predicate2]];

Obj-C - AND

NSPredicate *predicate1 = [NSPredicate predicateWithFormat:@"X == 1"];
NSPredicate *predicate2 = [NSPredicate predicateWithFormat:@"X == 2"];
NSPredicate *predicate = [NSCompoundPredicate andPredicateWithSubpredicates:@[predicate1, predicate2]];

Swift - OR

let predicate1:NSPredicate = NSPredicate(format: "X == 1")
let predicate2:NSPredicate = NSPredicate(format: "Y == 2")
let predicate:NSPredicate  = NSCompoundPredicate(orPredicateWithSubpredicates: [predicate1,predicate2] )

Swift - AND

let predicate1:NSPredicate = NSPredicate(format: "X == 1")
let predicate2:NSPredicate = NSPredicate(format: "Y == 2")
let predicate:NSPredicate  = NSCompoundPredicate(andPredicateWithSubpredicates: [predicate1,predicate2] )

Swift 3 - OR

    let predicate1 = NSPredicate(format: "X == 1")
    let predicate2 = NSPredicate(format: "Y == 2")
    let predicateCompound = NSCompoundPredicate.init(type: .or, subpredicates: [predicate1,predicate2])

Swift 3 - AND

    let predicate1 = NSPredicate(format: "X == 1")
    let predicate2 = NSPredicate(format: "Y == 2")
    let predicateCompound = NSCompoundPredicate.init(type: .and, subpredicates: [predicate1,predicate2])

Upvotes: 4

Dave DeLong
Dave DeLong

Reputation: 243146

You could do:

NSPredicate *p = [NSPredicate predicateWithFormat:@"attributeA contains[cd] $A OR attributeB contains[cd] $A or attributeC contains[cd] $A"];
NSDictionary *sub = [NSDictionary dictionaryWithObject:searchString forKey:@"A"];
p = [p predicateWithSubstitutionVariables:sub];

Or you could do something weirder, like this:

- (NSPredicate *)buildOrPredicate:(NSDictionary *)stuff {
  NSMutableArray *subs = [NSMutableArray array];
  for (NSString *key in stuff) {
    NSString *value = [stuff objectForKey:stuff];
    NSPredicate *sub = [NSPredicate predicateWithFormat:@"%K contains[cd] %@", key, value];
    [subs addObject:sub];
  }
  return [NSCompoundPredicate orPredicateWithSubpredicates:subs];
}

And then invoke that with:

NSDictionary *stuff = [NSDictionary dictionaryWithObjectsAndKeys:
                       searchString, @"attributeA",
                       searchString, @"attributeB",
                       searchString, @"attributeC",
                       nil];
NSPredicate *p = [self buildOrPredicate:stuff];

The only other thing I can think of that might work is to try using positional specifies in the predicate format. However, I don't know if the parser recognizes them the same way that +stringWithFormat: does:

NSPredicate *p = [NSPredicate predicateWithFormat:@"attributeA contains[cd] %1$@ OR attributeB contains[cd] %1$@ or attributeC contains[cd] %1$@", searchString];

Upvotes: 3

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