Tutorial by Examples: g

Since Qt 5.5 we have a new wonderful TreeView, a control we've all been waiting for. A TreeView implements a tree representation of items from a model. In general it looks like other QML views - ListView or TableView. But data structure of TreeView is more complex. A data in ListView or TableView...

myfunc(){ echo "I will never be executed." } another_func(){ # this "redeclare" overwrites original function myfunc(){ echo "I am the one and only"; } } # myfunc will print "I will never be executed" myfunc # but if we call another_func fi...

Django Admin comes with some Models registerd by default. There a some occasions where you might want to remove a Model from the admin pages. This is done in the admin submodule. If your app wass created using manage.py startapp, the admin.py file should already lay in your app module. Otherwise cr...

By default, queries that return entity types are tracking This means you can make changes to those entity instances and have those changes persisted by SaveChanges() Example : The change to the book rating will be detected and persisted to the database during SaveChanges(). using (va...

No tracking queries are useful when the results are used in a read-only scenario They are quicker to execute because there is no need to setup change tracking information Example : using (var context = new BookContext()) { var books = context.Books.AsNoTracking().ToList(); } With ...

Even if the result type of the query isn’t an entity type, if the result contains entity types they will still be tracked by default Example : In the following query, which returns an anonymous type, the instances of Book in the result set will be tracked using (var context = new BookC...

Sometimes we want to give extra information to our user with colors (for example red means something wrong has happened) We can change toast message background color using setting a color filter to the view which our toast give us (here I use a ColorMatrixColorFilter): Toast t = Toast.MakeText(con...

We can change our toast using SetGravity method. This method takes three parameters: first is gravity of toast on screen and two others set toast offset from the starting position (which is set by the first parameter): //Toast at bottom left corner of screen Toast t = Toast.MakeText(context, mess...

Usage To install a module (assuming cpanm is already installed): cpanm Data::Section cpanm ("cpanminus") strives to be less verbose than cpan but still captures all of the installation information in a log file in case it is needed. It also handles many "interactive questions&quo...

Every Keychain Item is most often represented as a CFDictionary. You can, however, simply use NSDictionary in Objective-C and take advantage of bridging, or in Swift you may use Dictionary and explicitly cast to CFDictionary. You could construct a password with the following dictionary: Swift var...

To construct a query, we need to represent it as a CFDictionary. You may also use NSDictionary in Objective-C or Dictionary in Swift and cast to CFDictionary. We need a class key: Swift var dict = [String : AnyObject]() dict[kSecClass as String] = kSecClassGenericPassword Next, we can specify...

As usual, we first need a CFDictionary to represent the item we want to update. This must contain all of the old values for the item, including the old private data. Then it takes a CFDictionary of any attributes or the data itself that you would like to change. So first, let's construct a class ke...

You can throw your own errors using error. Execution stops at uncaught errors. By default, the error message is "An error has occurred." with error number -2700. error error "An error has occurred." number -2700 from «script» to item You can pass a message with the error...

We need only one thing in order to delete an item from the Keychain: a CFDictionary with attributes describing the items to be deleted. Any items that match the query dictionary will be deleted permanently, so if you are only intending to delete a single item be sure to be specific with your query. ...

The JAR, WAR and EAR files types are fundamentally ZIP files with a "manifest" file and (for WAR and EAR files) a particular internal directory / file structure. The recommended way to create these files is to use a Java-specific build tool which "understands" the requirements f...

from PIL import Image im = Image.open("Image.bmp")

from __future__ import print_function import os, sys from PIL import Image for infile in sys.argv[1:]: f, e = os.path.splitext(infile) outfile = f + ".jpg" if infile != outfile: try: Image.open(infile).save(outfile) except IOError: ...

import sympy as sy # Symbols have to be defined before one can use them x = sy.S('x') # Definition of the equation to be solved eq=sy.Eq(x**2 + 2, 6) #Print the solution of the equation print sy.solve(eq) The result printed will be: [-2, 2]

This example is divided into two pillars SalaryCalculation Class : Calculating the net salary after tax deduction SalaryCalculationTests Class : For testing the method that calculates the net salary Step 1: Create Class Library, name it WagesLibrary or any appropriate name. Then rename the cl...

By default Controllers, ViewComponents and TagHelpers aren't registered and resolved via the dependency injection container. This results in the inability to do i.e. property injection when using a 3rd party Inversion of Control (IoC) container like AutoFac. In order to make ASP.NET Core MVC resolv...