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set alpha {a 1 b 2 c 3} dict get $alpha b # => 2 dict get $alpha d # (ERROR) key "d" not known in dictionary If dict get is used to retrieve the value of a missing key, an error is raised. To prevent the error, use dict exists: if {[dict exists $alpha $key]} { set result [d...

The DatePicker class has a property, SelectedDate, which enable you to get or set the selected date. If there is none selected, it means its value will be null. if (datePicker.SelectedDate == null) { // Do what you have to do }

You call use Thread.kill or Thread.terminate: thr = Thread.new { ... } Thread.kill(thr)

string is an alias to the .NET datatype System.String, which allows text (sequences of characters) to be stored. Notation: string a = "Hello"; var b = "world"; var f = new string(new []{ 'h', 'i', '!' }); // hi! Each character in the string is encoded in UTF-16, which mean...

Android developers(mainly beginners) have been confused regarding Internal & External storage terminology. There are lot of questions on Stackoverflow regarding the same. This is mainly because of the fact that terminology according to Google/official Android documentation is quite different to...

iOS 6 Within a single line, we can get an UUID like below: Swift let UDIDString = UIDevice.currentDevice().identifierForVendor?.UUIDString Objective-C NSString *UDIDString = [[[UIDevice currentDevice] identifierForVendor] UUIDString]; The identifierForVendor is an unique identifier that st...

var client = new MongoClient("mongodb://localhost:27017"); var database = client.GetDatabase("test"); var collection = database.GetCollection < Interactions > ("Interactions"); var newItem = new Interactions{ SiteName = "Example", Pages = ...

To add a child view controller: - (void)displayContentController:(UIViewController *)vc { [self addChildViewController:vc]; vc.view.frame = self.view.frame; [self.view addSubview:vc.view]; [vc didMoveToParentViewController:self]; } To remove a child view controller: - (void)hid...

First let's create an ExchangeManager object, where the constructor will connect to the services for us. It also has a GetOofSettings method, which will return the OofSettings object for the specified email address : using System; using System.Web.Configuration; using Microsoft.Exchange.WebServic...

Introduction Maps stores key/value pairs, where each key has an associated value. Given a particular key, the map can look up the associated value very quickly. Maps, also known as associate array, is an object that stores the data in form of keys and values. In Java, maps are represented using Ma...

DELETE FROM Helloworlds This will delete all the data from the table. The table will contain no rows after you run this code. Unlike DROP TABLE, this preserves the table itself and its structure and you can continue to insert new rows into that table. Another way to delete all rows in table is ...

TRUNCATE TABLE Helloworlds This code will delete all the data from the table Helloworlds. Truncate table is almost similar to Delete from Table code. The difference is that you can not use where clauses with Truncate. Truncate table is considered better than delete because it uses less transacti...

Static .Net library methods can be called from PowerShell by encapsulating the full class name in third bracket and then calling the method using :: #calling Path.GetFileName() C:\> [System.IO.Path]::GetFileName('C:\Windows\explorer.exe') explorer.exe Static methods can be called from the c...

trigger AccountTrigger on Account (before insert) { System.debug('Account(s) are about to be inserted'); }

trigger ContactTrigger on Contact (before insert, after insert, before update, after update, before delete, after delete, after undelete) { /** Before or After trigger execution**/ /...

trigger MyTrigger on SomeObject__c (after insert, after update) { if (Trigger.isAfter && Trigger.isInsert) { System.debug('The following records were inserted: '); for (SomeObject__c o : Trigger.new) { System.debug(o.Name); } } else if (Trigg...

Vaadin plug-in for eclipse provides a quick way to build vaadin project with Apache Ivy dependency manager. Vaadin's documentation explains how to create vaadin project with the help of Eclipse plugin. To install the plug-in just go to eclipse marketplace and search vaadin. Current version of the p...

To perform a query in Apex, surround the query with square brackets. The result can be assigned to a list, or to a single object. List<Account> allAccounts = [SELECT Id, Name FROM Account]; Account oldestAccount = [SELECT Id, Name FROM Account ORDER BY CreatedDate LIMIT 1];

To reference a variable in a query, add a colon (:) before the variable name. Datetime targetDate = Datetime.now().addDays(-7); List<Lead> recentLeads = [SELECT Id FROM Lead WHERE CreatedDate > :targetDate]; string targetName = 'Unknown'; List<Contact> incompleteContacts = [SELE...

When assigning to a single object, a query that returns anything other than a single row will throw a QueryException. try { Account a = [SELECT Id FROM Account WHERE Name = 'Non-existent Account']; } catch (QueryException e) { // List has no rows for assignment to SObject } try { ...