This page contains usage examples of NSPredicate, check here for Core Data usage examples 🔋 Get Demo CoreData / NSPredicate Xcode Project. Table of Contents Basic. Predicate Format and Arguments. String Format Specifier. Basic Comparison. Compound Comparison. Case insensitive Comparison. Reuse NSPredicate with.

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Examples of NSPredicate usage

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This page contains usage examples of NSPredicate, check here for Core Data usage examples 🔋

Basic

Techniques

Examples (Entity’s property…)

Predicate Format and Arguments

Say for a predicate which select Person that have a name “Asriel” and 50 money :

The format is 'name %@ AND money %i'.

%@ and %i are the format specifiers, %@ will be substituted with an object (eg: String, date etc), whereas %i will be substituted with an integer.

The substitution happens as illustrated below, following the order from left to right :

%@ (object format specifier) will be replaced with “Asriel” and %i (integer format specifier) will be replaced with 50. Asriel and 50 is the arguments.

After substitution, the predicate will become 'name 'Asriel' AND money = 50' , meaning the NSPredicate will find for Person that have name Asriel and 50 money.

But why can’t I just use “name ‘Asriel’ AND money = 50” instead of having to use the format specifier thingy?

Nspredicate Cheat Sheet Printable

Yes of course you can! For simple filter which require a hardcoded value I recommend using it. The format specifier substitution is for variable value usually, like this :

String Format Specifier

You can check the full list in Apple official documentation. %@ is used for objects like String, Date, Array etc.

%K is used for Keypath (the property of the entity).

Basic Comparison

Basic comparison symbol like , > , < etc.

Compound Comparison

Join two or more condition together with OR , AND.

Case insensitive Comparison

For case insensitive comparison, put [c] after the comparison symbol.

Reuse NSPredicate with substitution variable

As it is relatively time consuming for the app to parse the format string of the NSPredicate, we should try to reduce creating multiple NSPredicate and reuse similar NSPredicate as much as possible. We can use variable value in NSPredicate denoted by $ sign, and substitute its value by calling withSubstitutionVariables method.

You can use multiple variables like name BEGINSWITH $startingName AND money > $amount , then call withSubstitutionVariables(['startingName' : 'As', 'amount': 50]).

Using NSPredicate to filter Array of objects

Other than Core Data, we can also use NSPredicate to filter array of objects. The SELF in the format string means each individual element in the array.

Is included in an Array of values

Is not included in an Array of values

Begins with certain string

Contains certain string

Ends with certain string

Wildcard match with string

LIKE is used for wildcard match.

Wildcard match is used to match certain pattern of string, eg: to match img1.png , img10.png andimg100.png, we can use filename LIKE 'img*.png'. The * means zero or more characters between img and .png is accepted.

To match exactly one character, we can use ? , eg: filename LIKE 'img?.png' will match img1.png but not img10.png as it only take in one character between img and .png.

Regular Expression match with string

MATCHES is used for regular expression match.

Regular expression is used for complex string pattern matching. Swift uses ICU regular expression format.For learning regular expression, I recommend this tutorial.

Eg: filename MATCHES 'imgd{1,3}.png' will match filename with 1-3 digits between img and .png like img1.png, img10.png and img100.png but not img1000.png . Double backslash is used to escape the backslash character .

NSPredicate

NSPredicate, A definition of logical conditions used to constrain a search either for a fetch or for in-memory filtering. Predicates represent logical conditions, which you can use to filter collections of objects. Although it's common to create predicates directly from instances of NSComparisonPredicate, NSCompoundPredicate, and NSExpression, you often create predicates from a format string which is parsed by the class methods on NSPredicate.

NSPredicate, NSPredicate is a Foundation class that specifies how data should be fetched or filtered. Its query language, which is like a cross between a SQL WHERE clause and a regular expression, provides an expressive, natural language interface to define logical conditions on which a collection is searched. NSPredicate is a Foundation class that specifies how data should be fetched or filtered. Its query language, which is like a cross between a SQL WHERE clause and a regular expression, provides an expressive, natural language interface to define logical conditions on which a collection is searched.

NSPredicate Cheatsheet, returns the sum of the objects in the collection based on the property. [​NSPredicate predicateWithFormat: @'expenses.@avg.doubleValue Asriel and 50 is the arguments. After substitution, the predicate will become 'name 'Asriel' AND money = 50', meaning the NSPredicate will find for Person that have name Asriel and 50 money. But why can’t I just use “name ‘Asriel’ AND money = 50” instead of having to use the format specifier thingy? Yes of course you can!

Swift predicate cheat sheet

NSPredicate Cheatsheet, NSPredicate. This page contains usage examples of NSPredicate, check here for Core Data usage examples. Get Demo CoreData / NSPredicate Xcode This cheat sheet is a handy reference to keep you productive with Core Data and Swift! The code snippets below are here to help jog your memory when it’s been a while since you’ve worked in Core Data. They could also be helpful for newcomers to iOS development, Core Data, and Swift.

NSPredicate, returns objects where ALL of the predicate results are true. ALL returns objects where NONE of the predicate results are true. NONE. predicateWithFormat SUBQUERY(collection, variableName, predicate) A subquery takes a collection then iterates through each object (as variableName) checking the predicate against that object. It works well if you have a collection (A) objects, and each object has a collection (B) other objects. If you’re trying to filter A based on 2 or more varying attributes of B.

[PDF] NSPredicate Cheatsheet, NSPredicate is a Foundation class that specifies how data should be fetched or filtered. Its query language, which is like a cross between a Swift 5.1 Cheat Sheet and Quick Reference. Version 1.0.1. Declaring Constants and Variables // Declaring a constant using the let keyword let double: Double =

NSPredicate(format)

Predicate Format String Syntax, NSPredicate *predicate = [NSPredicate predicateWithFormat:@'%K like %@', attributeName, attributeValue]; The predicate format string in this case evaluates to firstName like 'Adam' . In the following example, the predicate format string evaluates to firstName like '%@' (note the single quotes around %@ ). Although it's common to create predicates directly from instances of NSComparisonPredicate, NSCompoundPredicate, and NSExpression, you often create predicates from a format string which is parsed by the class methods on NSPredicate. Examples of predicate format strings include: Simple comparisons, such as grade '7' or firstName like 'Shaffiq'

NSPredicate, NSPredicate is a Foundation class that specifies how data should be fetched let namesBeginningWithLetterPredicate = NSPredicate(format: NSPredicate is a Foundation class that specifies how data should be fetched or filtered. Its query language, which is like a cross between a SQL WHERE clause and a regular expression, provides an expressive, natural language interface to define logical conditions on which a collection is searched.

Examples of using NSPredicate to filter NSFetchRequest, commitPredicate = NSPredicate(format: 'message 'I fixed a bug in Swift'). That means 'make sure the message attribute is equal to this exact string.' Typing %@ (object format specifier) will be replaced with “Asriel” and %i (integer format specifier) will be replaced with 50. Asriel and 50 is the arguments. After substitution, the predicate will become 'name 'Asriel' AND money = 50', meaning the NSPredicate will find for Person that have name Asriel and 50 money.

Core Data fetch request swift 5

Loading Core Data objects using , The way fetch requests work is very simple: you create one from the NSManagedObject subclass you're using for your entity, then pass it to managed object Fetch requests allow us to load Core Data results that match specific criteria we specify, and SwiftUI can bind those results directly to user interface elements. If you followed my Core Data and SwiftUI set up instructions, you’ve already injected your managed object context into the SwiftUI environment. That step is required.

Core Data Programming Guide: Fetching Objects, The fetching of objects from Core Data is one of the most powerful features of You then call executeFetchRequest:error: on the NSManagedObjectContext and pass in Swift. let firstName = 'Trevor'; fetchRequest.predicate Usually, this shouldn't be a problem because an unsorted list in Core Data will always come back in an undefined order which, in my experience, is not desirable for most applications. The simplest way to fetch data using a fetch request while responding to any changes that impact your fetch request's results is to use an NSFetchResultsController. While this object is commonly used in conjunction with table views and collection views, we can also use it to drive a SwiftUI view.

Mastering In CoreData (Part 9 NSFetchRequest), The fetching of objects from Core Data is one of the most powerful features of Figure 1, A fetch request tells a Managed Object Context the entity of the In part 5 we discussed validation so comment out “User+CoreDataValidations.swift” file​ You should load all your Objects from CoreData into an Array/Dict of NSManaged Objects. Show activity on this post. let fetchRequest = NSFetchRequest(entityName: 'Locations') do { let results = try managedObjectContext.executeFetchRequest(fetchRequest) let locations = results as! [Locations] for location in locations { println(location) } } catch let error as NSError { print('Could not fetch (error)”) }

NSPredicate boolean

NSPredicate, This isn't really specific to NSPredicate Whenever you have %@ in a format string, the corresponding value must be a pointer to an object, I've got a boolean attr on an entity and the generated code for it is: @property (nonatomic, retain) NSNumber * countdownMode; @dynamic countdownMode; The entity is saved with: score.countdownMo

Core Data NSPredicate checking for BOOL value, NSPredicate boolean Swift. How to write a BOOL predicate in Core Data?, You specify and test for equality of Boolean values as illustrated in the Swift 4.0 let A class that represents an expression that, when evaluated, returns a boolean result.

NSPredicate, Returns a Boolean value indicating whether the specified object matches the conditions specified by the predicate after substituting in the values in a given Returns a Boolean value indicating whether the specified object matches the conditions specified by the predicate.

Core data predicate relationship

core data how to filter (NSPredicate) including a relationship , The predicate would be what you expect. NSPredicate(format: 'name = %@ && school = %@', 'Tom', school). However, you can get to the I have the following two entities in my Core Data Model: Manufacture {name, other attributes} Product {name, . other attributes} I have setup a One to Many Relationship: Manufacturer.manufactures <----->> Product.manufacturedBy I am trying to build a predicate to return all Products belonging to Manufacturers that match a search string.

Core Data on iOS 5 Tutorial: How To Work with Relations and , We've already worked with relationships in the Core Data model editor but predicates are what really makes fetching powerful in Core Data. If you are using the Core Data framework, you can use predicates in the same way as you would if you were not using Core Data (for example, to filter arrays or with an array controller). In addition, however, you can also use predicates as constraints on a fetch request and you can store fetch request templates in the managed object model (see Managed Object Models ).

Core Data and Swift: Relationships and More Fetching, In Core Data, this is represented using relationships, which are a bit like createFetchRequest() authorRequest.predicate = NSPredicate(format: 'name %@' Open Core_Data.xcdatamodeld, select the Person entity, and create a relationship named children. Set the destination to Person , set the type to To Many , and leave the inverse relationship empty for now.

NSCompoundPredicate

A subtype of NSPredicate that is used to calculate Boolean logical operations.

Use NSCompoundPredicate to create an AND or OR compound predicate of zero or more other predicates, or the NOT of a single predicate. For the logical AND and OR operations: An AND predicate with no subpredicates evaluates to true. An OR predicate with no subpredicates evaluates to false.

NSCompoundPredicate(NSObjectFlag) Constructor to call on derived classes to skip initialization and merely allocate the object. NSCompoundPredicate(IntPtr) A constructor used when creating managed representations of unmanaged objects; Called by the runtime. NSCompoundPredicate(NSCompoundPredicateType, NSPredicate[])

NSPredicate contains

NSPredicate Cheatsheet, Format string summary. @'attributeName %@' object's attributeName value is equal to value passed in. Keypath collection queries. @avg. returns the average of the objects in the collection as an NSNumber. Object, array, and set operators. @distinctUnionOfObjects. Array operations. array[index] Although it's common to create predicates directly from instances of NSComparisonPredicate, NSCompoundPredicate, and NSExpression, you often create predicates from a format string which is parsed by the class methods on NSPredicate. Examples of predicate format strings include: Simple comparisons, such as grade '7' or firstName like 'Shaffiq'. Case and diacritic insensitive lookups, such as name contains [cd] 'itroen'.

NSPredicate contains string lowercase, This is how I've solved my problem: if ((shopSearchBar.text != nil) && ([​shopSearchBar.text length] > 0)) { NSPredicate *predicate var predicateList = [NSPredicate]() let words = filterText.componentsSeparatedByString(' ') for word in words{ if count(word)0{ continue } let firstNamePredicate = NSPredicate(format: 'firstName contains[c] %@', word) let lastNamePredicate = NSPredicate(format: 'lastName contains[c] %@', word) let departmentPredicate = NSPredicate(format: 'department contains[c] %@', word) let jobTitlePredicate = NSPredicate(format: 'jobTitle contains[c] %@', word) let orCompoundPredicate

NSPredicate, Using NSPredicate with Collections​​ Mutable collections, NSMutableArray & NSMutableSet have the method filterUsingPredicate: , which removes any objects that evaluate to FALSE when running the predicate on the receiver. NSDictionary can use predicates by filtering its keys or values (both NSArray objects). NSPredicate is a Foundation class that specifies how data should be fetched or filtered. Its query language, which is like a cross between a SQL WHERE clause and a regular expression, provides an expressive, natural language interface to define logical conditions on which a collection is searched. It’s easier to show NSPredicate in use, rather than talk about it in the abstract, so we’re going to revisit the example data set used in the NSSortDescriptor article:

NSPredicate date

NSPredicate: filtering objects by day of NSDate property, date(from: components) return NSPredicate(format: 'day >= %@ AND day =< %@', argumentArray: [startDate!, endDate!]) } } NSPredicate *pred = [NSPredicate predicateWithFormat: [NSString stringWithFormat: @'dataGiorno >= '%@', [dateFormatter dateFromString:@'31-12-2013']]]; With this one : NSPredicate *pred = [NSPredicate predicateWithFormat:@'dataGiorno >= '%@', [dateFormatter dateFromString:@'31-12-2013']]; No need to use an extra NSString here.

Examples of using NSPredicate to filter NSFetchRequest, I've made that an optional NSPredicate because that's exactly what our fetch commitPredicate = NSPredicate(format: 'date > %@', twelveHoursAgo as When used with Date, you can set an instance of NSPredicate by casting your Date instance to NSDate as indicated below: let date = Date() let predicate = NSPredicate(format: 'date > %@', date as NSDate) #4. Using NSPredicate init(format: arguments: ) initializer with Date instance casted to CVarArg. When used with Date, you can set an instance of NSPredicate by casting your Date instance to CVarArg as indicated below: let date = Date() let predicate = NSPredicate(format: 'date > %@', date as

NSPredicate, is used for objects like String, Date, Array etc. %K is used for Keypath (the property of the entity). let integerPredicate = NSPredicate(format: 'money %i',​ Questions: I’m trying to make a fetch for dates later than a specific date. My predicate is as follows: NSPredicate(format: 'date > (currentDate)') When I executed the fetch request I caught an exception: 'Unable to parse the format string 'date > 2015-07-08 03:00:00 +0000' I thought I could make a query like that.

Nspredicate Cheat Sheet Pdf

SwiftUI FetchRequest predicate

Dynamically filtering @FetchRequest with SwiftUI, Dynamically filtering @FetchRequest with SwiftUI dynamically change a Core Data Duration: 10:20Posted: Feb 20, 2020 NSFetchRequest request.predicate = NSPredicate(format: 'status%@', status as String) // warning: FetchRequest must have a sort descriptor request.sortDescriptors = [NSSortDescriptor(key: 'createTime', ascending: true)] return request } } In this way, you can dynamic change your NSPredicate or NSSortDescriptor.

How to filter Core Data fetch requests using a predicate, Core Data fetch requests can use predicates in SwiftUI just like they can with UIKit, all by providing a predicate property to your @FetchRequest property wrapper. If you followed my Core Data and SwiftUI set up instructions, you've already injected your managed object context into the SwiftUI environment. Core Data fetch requests can use predicates in SwiftUI just like they can with UIKit, all by providing a predicate property to your @FetchRequest property wrapper. If you followed my Core Data and SwiftUI set up instructions, you’ve already injected your managed object context into the SwiftUI environment.

SwiftUI View and @FetchRequest predicate with variable that can , had the same problem, and a comment of Brad Dillon showed the solution: var predicate:String var wordsRequest : FetchRequest<Word> var How to update FetchRequest with predicate in SwiftUI. Khoa Pham. Follow. Mar 14, 2020

NSPredicate multiple conditions Swift

Combining Two Conditions in NSPredicate, Combining Two Conditions in NSPredicate · swift nspredicate. How do you combine two conditions in NSPredicate ? I am using the following let p1 = NSPredicate(format: 'username = %@', 'user') let p2 = NSPredicate(format: 'password = %@', 'password') let predicate = NSCompoundPredicate(andPredicateWithSubpredicates: [p1, p2]) This is useful for more complex expressions, or if you want to build a predicate dynamically at runtime.

Multiple conditions in NSPredicate, placePredicate = [NSPredicate predicateWithFormat:@'place Note that I don't bother even putting into the array the predicate for category (or anything For further you can read this article Array Filter Using Blocks. In Swift. NSPredicate with Multiple Condition - Execute second condition based on first condition I need to fetch data from Core data, for that , I need to check Condition1 and Condition 2 using **NSPredicate**.

Multiple conditions in NSPredicate, Multiple conditions in predicate swift. Combining Two Conditions in NSPredicate, Combining Two Conditions in NSPredicate · swift nspredicate. How do you Overview Predicates represent logical conditions, which you can use to filter collections of objects. Although it's common to create predicates directly from instances of NSComparisonPredicate, NSCompoundPredicate, and NSExpression, you often create predicates from a format string which is parsed by the class methods on NSPredicate.

Nspredicate Cheat Sheet

Core data predicate date

Core Data- predicate with dates, Firstly you need to define your date range. To do that you'll want to start with today's date and then add a weeks worth of days to find the end of the valid range. Once you have that range you can build your predicate to find all tasks with a due date >= start and <= end. let fetchRequest: NSFetchRequest = Order.fetchRequest() let date_formatter = DateFormatter() date_formatter.dateFormat = 'yyyy-MM-dd-HH-mm-ss' date_formatter.timeZone = TimeZone(abbreviation: 'UTC') let createdDate = date_formatter.date(from: clientCreatedStr) let calendar = NSCalendar.current //as matching exact same datetime doesnt return anything let onesecondafter = calendar.date(byAdding: .second, value: 1, to: createdDate!) let onesecondbefore = calendar.date(byAdding: .second, value

Get Core Data entries between a date range · GitHub, Build the predicate. NSPredicate *predicate = [NSPredicate predicateWithFormat: @'date >= %@ && date <= %@ ', fromDate, toDate];. request.predicate Core Data. This page contain this line if you want to update all persons updateRequest. predicate 10000000000 person. married = true person. birthday = Date

Examples of using NSPredicate to filter NSFetchRequest, Predicates are one of the most powerful features of Core Data, but they are actually useful For a third and final predicate, let's try filtering on the 'date' attribute. CoreData predicate with dates. Zerho. Aug 17th, 2013. it only occurs while i put dates) NSPredicate * predicate = RAW Paste Data

Nspredicate Cheat Sheet 2020

Nspredicate Cheat Sheet Template

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