Tutorial by Examples: ed

Please read Preventing SQL injection with Parametrized Queries for a complete discussion of why prepared statements help you secure your SQL statements from SQL Injection attacks The $conn variable here is a MySQLi object. See MySQLi connect example for more details. For both examples, we assume t...

How do you go about using an instance of a (possibly further) inherited generic type within a method declaration in the generic type itself being declared? This is one of the problems you will face when you dig a bit deeper into generics, but still a fairly common one. Assume we have a DataSeries&l...

While redux itself is entirely synchronous, you can use a middleware such as redux-thunk to handle asynchronous actions. A "thunk" is another name for a callback. It is a function that is usually passed as an argument to be called at a later time. To use, apply the middleware to you...

const loadUser = userId => dispatch => { dispatch({ type: 'USER_LOADING' }); $.ajax('/users/' + userId, { type: 'GET', dataType : 'json' }).done(response => { dispatch({ type: 'USER_LOADED', user: response }); }).fail((xhr, status, error) =>...

public final class DrawerLayoutTest { @Test public void Open_Close_Drawer_Layout() { onView(withId(R.id.drawer_layout)).perform(actionOpenDrawer()); onView(withId(R.id.drawer_layout)).perform(actionCloseDrawer()); } public static ViewAction actionOpenDrawer() { return ne...

Setup First, install the necessary packages with: npm install express cors mongoose Code Then, add dependencies to your server.js file, create the database schema and the name of the collection, create an Express.js server, and connect to MongoDB: var express = require('express'); var cors =...

We often encounter a situation where a property we're trying to extract doesn't exist in the object/array, resulting in a TypeError (while destructuring nested objects) or being set to undefined. While destructuring we can set a default value, which it will fallback to, in case of it not being found...

We are not limited to destructuring an object/array, we can destructure a nested object/array. Nested Object Destructuring var obj = { a: { c: 1, d: 3 }, b: 2 }; var { a: { c: x, d: y }, b: z } = obj; console.log(x, y, z); // 1,3,2 Nested Array ...

The following are the steps to start an Eclipse remote debugger. This is useful when the application is not started from a server instance within Eclipse. This feature is really powerful and can also help debugging code which resides in the test or production environment. Let's have a look at the se...

Sample Data: CREATE TABLE table_name ( value VARCHAR2(50) ); INSERT INTO table_name ( value ) VALUES ( 'A,B,C,D,E' ); Query: WITH items ( list, item, lvl ) AS ( SELECT value, REGEXP_SUBSTR( value, '[^,]+', 1, 1 ), 1 FROM table_name UNION ALL SELECT value, ...

Appearance : Trying to access an array by a key that does not exist in the array Possible Solution : Check the availability before accessing it. Use: isset() array_key_exists()

Assume an application with a MainActivity which can call the Next Activity using a button click. public class MainActivity extends AppCompatActivity { private final String LOG_TAG = MainActivity.class.getSimpleName(); @Override protected void onCreate(Bundle savedInstanceState) { ...

The below code example will give you an adjusted version of that color where a higher percentage will be brighter and a lower percentage will be darker. Objective-C + (UIColor *)adjustedColorForColor:(UIColor *)c : (double)percent { if (percent < 0) percent = 0; CGFloat r, g, b...

Simple case without duplicate keys Stream<String> characters = Stream.of("A", "B", "C"); Map<Integer, String> map = characters .collect(Collectors.toMap(element -> element.hashCode(), element -> element)); // map = {65=A, 66=B, 67=C} ...

When a user press F1 on a control or click on Help button of form (?) and then clicks on a control the HelpRequested event will be raised. You can handle this event to provide custom action when user requests help for controls or form. The HelpRequested supports bubble up mechanism. It fires for y...

You can detect when a user Clicked on a HelpButton on title-bar of form by handling HelpButtonClicked. You can let the event continue or cancel it by setting Cancel property of its event args to true. private void Form1_HelpButtonClicked(object sender, CancelEventArgs e) { e.Cancel = true; ...

The protected internal keyword marks field, methods, properties and nested classes for use inside the same assembly or derived classes in another assembly: Assembly 1 public class Foo { public string MyPublicProperty { get; set; } protected internal string MyProtectedInternalPropert...

First make utility class or use this method in class needed public class UIUtils { public static BitmapImageViewTarget getRoundedImageTarget(@NonNull final Context context, @NonNull final ImageView imageView, final float radius) { retur...

Subroutine arguments in Perl are passed by reference, unless they are in the signature. This means that the members of the @_ array inside the sub are just aliases to the actual arguments. In the following example, $text in the main program is left modified after the subroutine call because $_[0] in...

The code below implements a very simple complex number type for which the underlying field is automatically promoted, following the language's type promotion rules, under application of the four basic operators (+, -, *, and /) with a member of a different field (be it another complex<T> or so...