Tutorial by Examples: u

Even when all your work is directed at a single worksheet, it's still a very good practice to explicitly specify the worksheet in your code. This habit makes it much easier to expand your code later, or to lift parts (or all) of a Sub or Function to be re-used someplace else. Many developers establi...

A module is an importable file containing definitions and statements. A module can be created by creating a .py file. # hello.py def say_hello(): print("Hello!") Functions in a module can be used by importing the module. For modules that you have made, they will need to be in t...

This object, Shape has a property image that depends on numberOfSides and sideWidth. If either one of them is set, than the image has to be recalculated. But recalculation is presumably long, and only needs to be done once if both properties are set, so the Shape provides a way to set both propertie...

A Closure is a function taken together with an environment. The function is typically an anonymous function defined inside another function. The environment is the lexical scope of the enclosing function (very basic idea of a lexical scope of a function would be the scope that exists between the fun...

Suppose you have many changes in one or more files but from each file you only want to commit some of the changes, you can select the desired changes using: git add -p or git add -p [file] Each of your changes will be displayed individually, and for each change you will be prompted to choose...

First, ensure you have imported sessions from flask from flask import session To use session, a Flask application needs a defined SECRET_KEY. app = Flask(__name__) app.secret_key = 'app secret key' Sessions are implemented by default using a cookie signed with the secret key. This ensures t...

props are used to pass data and methods from a parent component to a child component. Interesting things about props They are immutable. They allow us to create reusable components. Basic example class Parent extends React.Component{ doSomething(){ console.log("Parent comp...

defaultProps allows you to set default, or fallback, values for your component props. defaultProps are useful when you call components from different views with fixed props, but in some views you need to pass different value. Syntax ES5 var MyClass = React.createClass({ getDefaultProps: ...

componentWillReceiveProps(nextProps) This is the first function called on properties changes. When component's properties change, React will call this function with the new properties. You can access to the old props with this.props and to the new props with nextProps. With these variables, you c...

NSArray *myColors = @[@"Red", @"Green", @"Blue", @"Yellow"]; // Fast enumeration // myColors cannot be modified inside the loop for (NSString *color in myColors) { NSLog(@"Element %@", color); } // Using indices for (NSUInteger i = 0; ...

With automatic reference counting (ARC), the compiler inserts retain, release, and autorelease statements where they are needed, so you don't have to write them yourself. It also writes dealloc methods for you. The sample program from Manual Memory Management looks like this with ARC: @interface M...

This is an example of a program written with manual memory management. You really shouldn't write your code like this, unless for some reason you can't use ARC (like if you need to support 32-bit). The example avoids @property notation to illustrate how you used to have to write getters and setters....

The installation instructions are available on IIS.net. See this for installing IIS 8.5

when the object is saved/updated, check the associations and save/update any object that require it (including save/update the associations in many-to-many scenario).

Send an HTTP response with status code 200 to indicate a successful request. The HTTP response status line is then: HTTP/1.1 200 OK The status text OK is only informative. The response body (message payload) should contain a representation of the requested resource. If there is no representation...

Assuming that you have successfully created a JFrame and that Swing has been imported... You can import Swing entirely import javax.Swing.*; or You can import the Swing Components/Frame that you intend to use import javax.Swing.Jframe; import javax.Swing.JButton; Now down to adding the J...

PHP is a loosely typed language. This means that, by default, it doesn't require operands in an expression to be of the same (or compatible) types. For example, you can append a number to a string and expect it to work. var_dump ("This is example number " . 1); The output will be: ...

Switch statements use non-strict comparison to determine matches. This can lead to some nasty surprises. For example, consider the following statement: switch ($name) { case 'input 1': $mode = 'output_1'; break; case 'input 2': $mode = 'output_2'; bre...

When you install Oracle 11g or 12cR1, an older version of Apex is pre-installed. It is highly recommended to upgrade it to the latest version. Go to apex.oracle.com and download the latest version of Apex. Follow the documentation for the specific version to install it. Important Docu...

Add the following dependency to the build.gradle file: compile 'com.nostra13.universalimageloader:universal-image-loader:1.9.5' Add the following permissions to the AndroidManifest.xml file: <uses-permission android:name="android.permission.INTERNET" /> <uses-permiss...