I'm building a NSPredicate using the code below for an iPhone app. The logging shows the prediate to be: location CONTAINS "head" AND shape CONTAINS "oval" AND texture CONTAINS "bumpy" AND colour CONTAINS "red"
I get no results. If I limit the predicate to a single item it will work, more than 1 fails.
Can anyone tell me why?
Many thanks
NSMutableArray *subPredicates = [[NSMutableArray alloc] init];
for (Ditem in self.tableDataSource) {
NSString *Title = [Ditem valueForKey:#"Title"];
NSString *Value = [Ditem valueForKey:#"Value"];
if([[Value lowercaseString] isEqualToString: #"all"]){
Value = #"";
}
else{
NSPredicate *p = [NSComparisonPredicate predicateWithLeftExpression:[NSExpression expressionForKeyPath:[Title lowercaseString]] rightExpression:[NSExpression expressionForConstantValue:[Value lowercaseString]] modifier:NSDirectPredicateModifier type:NSContainsPredicateOperatorType options:0];
[subPredicates addObject:p];
}
}
NSPredicate *predicate = [NSCompoundPredicate andPredicateWithSubpredicates:subPredicates];
NSLog(#"predicate: %#", predicate);[self.fetchedResultsController.fetchRequest setPredicate:predicate];
Your predicate is requiring that all of the values in your filterable objects be strings. Is that correct?
Also, I would simplify your subpredicate creation to:
NSPredicate * p = [NSPredicate predicateWithFormat:#"%K CONTAINS %#", [Title lowercaseString], [Value lowercaseString]];
Related
My Array
(
{id:1,data:(#"macbook",#"mac mini")},
{id:2,data:(#"ipad",#"ipod")},
{id:3,data:(#"macbook",#"ipod")}
)
I have a predicate
NSString *text = #"mac";
[NSPredicate predicateWithFormat:#"(data contains[cd] %#)",text];
[array filteredArrayUsingPredicate:predicate];
but it doesn't loop over my array inside my dictionary
(my result should be an array containing 2 objects with id 1 and 3)
NSString* text = #"mac" ;
NSPredicate* predicate = [NSPredicate predicateWithFormat:#"any data contains[cd] %#",text] ;
NSArray* filteredArray = [theArray filteredArrayUsingPredicate:predicate] ;
I personally find NSPredicate formats very error prone.
You may consider using a block in order to filter your NSArray
NSString * filterString = #"mac";
NSIndexSet * indexes = [array indexesOfObjectsPassingTest:^BOOL(id obj, NSUInteger idx, BOOL *stop) {
NSArray * entry = obj[#"data"];
for (NSString * value in entry)
if ([value rangeOfString:filterString].location != NSNotFound)
return YES;
return NO;
}];
NSArray * filteredArray = [array objectsAtIndexes:indexes];
It's definitely longer and more verbose, but I find it definitely easier to read and debug.
I've been trying to filter this array (which is full of NSDictionaries) using NSPredicate...
I have a very small amount of code that just isn't working...
The following code should change label.text to AmyBurnett34, but it doesn't...
NSPredicate *pred = [NSPredicate predicateWithFormat:#"id = %#", [[mightyPlistDict objectForKey:#"pushesArr"] objectAtIndex:indexPath.row]];
NSLog(#"%#",pred);
label.text = [[[twitterInfo filteredArrayUsingPredicate:pred] lastObject] objectForKey:#"screen_name"];
NSLog(#"%#",twitterInfo);
And here is what gets NSLoged...
2012-08-05 11:39:45.929 VideoPush[1711:707] id == "101323790"
2012-08-05 11:39:45.931 VideoPush[1711:707] (
{
id = 101323790;
"screen_name" = AmyBurnett34;
},
{
id = 25073877;
"screen_name" = realDonaldTrump;
},
{
id = 159462573;
"screen_name" = ecomagination;
},
{
id = 285234969;
"screen_name" = "UCB_Properties";
},
{
id = 14315150;
"screen_name" = MichaelHyatt;
}
)
Just for the heads up if you also NSLog this... the array is empty...
NSLog(%#,[twitterInfo filteredArrayUsingPredicate:pred]);
The problem is that your predicate is using comparing with a string and your content is using a number. Try this:
NSNumber *idNumber = [NSNumber numberWithLongLong:[[[mightyPlistDict objectForKey:#"pushesArr"] objectAtIndex:indexPath.row] longLongValue]];
NSPredicate *pred = [NSPredicate predicateWithFormat:#"id = %#", idNumber];
You don't know for sure that the value of "id" is a string - it might be a NSNumber. I suggest:
NSUInteger matchIdx = ...;
NSUInteger idx = [array indexOfObjectPassingTest:^BOOL(NSDictionary *dict, NSUInteger idx, BOOL *stop)
{
id obj = [dict objectForKey:#"id"];
// NSLog the class if curious using NSStringFromClass[obj class];
NSUInteger testIdx = [obj integerValue]; // works on strings and numbers
return testIdx == matchIdx;
}
if(idx == NSNotFound) // handle error
NSString *screenName = [[array objectAtIndex:idx] objectForKey:#"screen_name"];
NSPredicate is used for filtering arrays, not sorting them.
To sort an array, use the sortedArrayUsingDescriptors method of NSArray.
An an example:
// Define a sort descriptor based on last name.
NSSortDescriptor *descriptor = [[NSSortDescriptor alloc] initWithKey:#"lastName" ascending:YES];
// Sort our array with the descriptor.
NSArray *sortedArray = [originalArray sortedArrayUsingDescriptors:[NSArray arrayWithObjects:descriptor, nil]];
In my application i have a large table of around 12000 entries. I am displaying it on tableview. But the search bar is too slow while doing dynamic search. I have read that NSPredicate method is more permorfant then NSRange.
This is my old the code:
[self.filteredListContent removeAllObjects];
listContent = [[NSArray alloc] initWithArray:[dbAccess getAllBooks]];
for (Book *book in listContent)
{
NSRange range = [book.textBook rangeOfString:searchText options:NSCaseInsensitiveSearch];
if (range.location != NSNotFound)
{
[self.filteredListContent addObject:book];
}
}
My new code:
[self.filteredListContent removeAllObjects];
listContent = [[NSArray alloc] initWithArray:[dbAccess getAllBooks]];
NSPredicate *predicate = [NSPredicate predicateWithFormat:#"SELF like[c] %#",searchText];
[self.filteredListContent addObject:[listContent filteredArrayUsingPredicate:predicate]];
When i try to execute this code i received this error: "Can't do regex matching on object .'"
I would do something more like...
NSPredicate *predicate = [NSPredicate predicateWithFormat:#"%k like[c] %#",propertyIAmLookingFor,searchText];
Is your book class a string? If not then you cant use SELF like. You need to substitute the name of the property you are comparing.
I would know how retrieve an index of an NSArray using a NSPredicate ?
NSArray *array = [NSArray arrayWithObjects:
#"New-York City",
#"Washington DC",
#"Los Angeles",
#"Detroit",
nil];
Which kind of method should I use in order to get the index of "Los Angles" by giving only a NSString?
NB: #"Los An" or #"geles" should return the same index.
Using NSPredicate you can get array of strings that contain your search string (it seems there's no built-in method to get just element indexes):
NSPredicate *predicate = [NSPredicate predicateWithFormat:#"SELF CONTAINS[cd] %#", searchString];
NSArray *filteredArray = [array filteredArrayUsingPredicate: predicate];
You can get only indexes using indexesOfObjectsPassingTest: method:
NSIndexSet *indexes = [array indexesOfObjectsPassingTest:^BOOL(id obj, NSUInteger idx, BOOL *stop){
NSString *s = (NSString*)obj;
NSRange range = [s rangeOfString: searchString];
return range.location != NSNotFound;
}];
If you want to get just one element containing your string you can use similar indexOfObjectPassingTest: method for that.
You should be able to do this with blocks. Below is a snippet (I don't have a compiler handy so pls excuse any typos):
NSArray *array = [NSArray arrayWithObjects:
#"New-York City",
#"Washington DC",
#"Los Angeles",
#"Detroit",
nil];
NSString *matchCity = #"Los";
NSPredicate *predicate = [NSPredicate predicateWithFormat:#"SELF contains[cd] %#", matchCity];
NSUInteger index = [self.array indexOfObjectPassingTest:^(id obj, NSUInteger idx, BOOL *stop) {
return [predicate evaluateWithObject:obj];
}];
Essentially you can use the indexOfObjectPassingTest: method. This takes a block (code following the "^") and returns the index for the first object that matches your predicate (or NSNotFound if no match exists). The block iterates through each object in the array until either a match is found (at which point it returns the index) or no match is found (at which point it returns NSNotFound). Here is a link to block programming that can help you understand the logic within the block:
https://developer.apple.com/library/ios/featuredarticles/Short_Practical_Guide_Blocks/
Found an alternative approach helpful where the search is more complex as it allows predicate to be used to find object then object to find index:
-(NSIndexPath*) indexPathForSelectedCountry{
NSUInteger indexToCountry = 0;
NSPredicate * predicate = [NSPredicate predicateWithFormat:#"isoCode = %#",self.selectedCountry.isoCode];
NSArray * selectedObject = [self.countryList filteredArrayUsingPredicate:predicate];
if (selectedObject){
if (self.searchDisplayController.isActive){
indexToCountry = [self.searchResults indexOfObject:selectedObject[0]];
}else{
indexToCountry = [self.countryList indexOfObject:selectedObject[0]];
}
}
return [NSIndexPath indexPathForRow:indexToCountry inSection:0];
}
I would do this..
NSString * stringToCompare = #"geles";
int foundInIndex;
for ( int i=0; i<[array count]; i++ ){
NSString * tryString = [[array objectAtIndex:i] description];
if ([tryString rangeOfString:stringToCompare].location == NSNotFound) {
// no match
} else {
//match found
foundInIndex = i;
}
}// end for loop
Based on #Louie answer, instead of using for loop i had used enumeration block which worked for me.
I did this :-
NSString *stringToCompare = #"xyz";
[myArray enumerateObjectsUsingBlock:^(id *Obj, NSUInteger idx, BOOL * _Nonnull stop) {
NSString * tryString = [[myArray objectAtIndex:idx] description];
if ([tryString rangeOfString:stringToCompare].location == NSNotFound) {
// no match found
} else {
//match found and perform your operation. In my case i had removed array object at idx
}
}];
Hi the problem goes like this:
I have in CoreData entities that have a title and a relationship to keywords entities.
I need a predicate that helps me to fetch all those entities whose title contains the keywords I type. I have the code below that should do this but it doesn't:
NSArray *keywords = [searchString componentsSeparatedByString:#" "];
NSString *predicateString = #"";
for(NSInteger i = 0; i < [keywords count]; i++) {
if(((NSString*)[keywords objectAtIndex:i]).length != 0) {
if(i==0) {
predicateString = [keywords objectAtIndex:i];
}
else {
predicateString = [predicateString stringByAppendingFormat:#" and keywords.normalizedKeyword contains[cd] %#", [keywords objectAtIndex:i]];
}
}
}
NSPredicate *predicate = [NSPredicate predicateWithFormat:#"keywords.normalizedKeyword contains[cd] %#",predicateString];
For example I have entities with titles like this:
1) "Great Coloring theme"
2) "Theme for kids"
3) "Cars for kids"
my keywords db will contain:
great
coloring
theme
for
kids
cars
How can I create a predicate so when I type for example:
Theme for
the result will be 2) and 3)
or if I type:
great theme
the result will be 1) and 2)
Any help in getting the right predicate to achieve this is very much appreciated. What I tried to do there it doesn't work and I am out of ideas.
Thanks!
I have found the answer myself. To solve such a problem you have to use a NSCompoundPredicate.
The solution to my problem was this:
NSArray *keywords = [lowerBound componentsSeparatedByString:#" "];
NSMutableArray *predicates = nil;
for(NSInteger i = 0; i < [keywords count]; i++) {
if(((NSString*)[keywords objectAtIndex:i]).length != 0) {
NSPredicate *predicate = [NSPredicate predicateWithFormat:#"keywords.normalizedKeyword contains[cd] %#", [keywords objectAtIndex:i]];
if(predicates == nil) {
predicates = [[NSMutableArray alloc] initWithCapacity:0];
}
[predicates addObject:predicate];
}
}
NSPredicate *compoundPredicate = [NSCompoundPredicate andPredicateWithSubpredicates:predicates];