Tutorial by Examples: g

The :on option lets you specify when the validation should happen. The default behavior for all the built-in validation helpers is to be run on save (both when you're creating a new record and when you're updating it). class Person < ApplicationRecord # it will be possible to update email wi...

The simplest way to get an event handler called on a key press is to connect the handler to the key-press-event signal. In this example, we register for the event for the whole window, but you can also register for individual widgets too. The most important part is the connection of the handler to ...

UIView *view = [[UIView alloc] init]; [self.view addSubview:view]; //Use the function if you want to use height as constraint [self addView:view onParentView:self.view withHeight:200.f]; //Use this function if you want to add view with respect to parent and should resize with it [self a...

To help you find and count characters in a string, CharMatcher provides the following methods: int indexIn(CharSequence sequence) Returns the index of the first character that matches the CharMatcher instance. Returns -­1 if no character matches. int indexIn(CharSequence sequence, int sta...

var source = new AutoCompleteStringCollection(); // Add your collection of strings. source.AddRange(new[] { "Guybrush Threepwood", "LeChuck" }); var textBox = new TextBox { AutoCompleteCustomSource = source, AutoCompleteMode = AutoCompleteMode.SuggestAppend, ...

textBox.KeyPress += (sender, e) => e.Handled = !char.IsControl(e.KeyChar) && !char.IsDigit(e.KeyChar); This will only permit the use of digits and control characters in the TextBox, other combinations are possible using the same approach of setting the Handle property to true to block ...

A StringBuilder represents a series of characters, which unlike a normal string, are mutable. Often times there is a need to modify strings that we've already made, but the standard string object is not mutable. This means that each time a string is modified, a new string object needs to be created,...

You can configure the database settings in config/connections.js. Here's an example: postgresql: { database: 'databaseName', host: 'localhost', user: 'root', password: '', port: 5432, poolSize: 10, ssl: false }; Alternatively, you can supply the connection information in U...

Sometimes we want the model to give more weight to some data points or examples than others. This is possible by specifying the weight for the input data while learning the model. There are generally two kinds of scenarios where we might use non-uniform weights over the examples: Analytic Weights...

Short circuiting is a functionality that skips evaluating parts of a (if/while/...) condition when able. In case of a logical operation on two operands, the first operand is evaluated (to true or false) and if there is a verdict (i.e first operand is false when using &&, first operand is tr...

If you are using Leiningen and your tests are located in the test directory in your project root then you can run your tests using lein test

Lazy loading is enabled by default. Lazy loading is achieved by creating derived proxy classes and overriding virtual navigation proeprties. Lazy loading occurs when property is accessed for the first time. int companyId = ...; Company company = context.Companies .First(m => m.Id == compan...

Eager loading lets you load all your needed entities at once. If you prefer to get all your entities to work on in one database call, then Eager loading is the way to go. It also lets you load multiple levels. You have two options to load related entities, you can choose either strongly typed or st...

After turning Lazy loading off you can lazily load entities by explicitly calling Load method for entries. Reference is used to load single navigation properties, whereas Collection is used to get collections. Company company = context.Companies.FirstOrDefault(); // Load founder context.Entry(com...

The most common way is to apply the extension via Config. Example: # File: mysite/_config/config.yml Member: extensions: - MyMemberExtension The extensions config variable is of type "array", so you can add multiple extensions like this: # File: mysite/_config/config.yml Mem...

Some procedures have optional arguments. Optional arguments always come after required arguments, but the procedure can be called without them. For example, if the function, ProcedureName were to have two required arguments (argument1, argument2), and one optional argument, optArgument3, it could b...

library(gpuR) # gpuMatrix objects X <- gpuMatrix(rnorm(100), 10, 10) Y <- gpuMatrix(rnorm(100), 10, 10) # transfer data to GPU when operation called # automatically copied back to CPU Z <- X %*% Y

library(gpuR) # vclMatrix objects X <- vclMatrix(rnorm(100), 10, 10) Y <- vclMatrix(rnorm(100), 10, 10) # data always on GPU # no data transfer Z <- X %*% Y

From MSDN Use the CInt function to provide conversions from any other data type to an Integer subtype. For example, CInt forces integer arithmetic when currency, single-precision, or double-precision arithmetic would normally occur. Assuming that you have 1 button and 2 textbox. If you type...

TRACE and DEBUG log levels are there to be able to convey high detail about the operation of the given code at runtime. Setting the log level above these is usually recommended, however some care must be taken for these statements to not affect performance even when seemingly "turned off"....