Tutorial by Examples: pre

If you like to organize your project by keeping source files in different subdirectories, you should know that during a build qmake will not preserve this directory structure and it will keep all the ".o" files in a single build directory. This can be a problem if you had conflicting file ...

SELECT DATE('2003-12-31 01:02:03'); The output will be: 2003-12-31

Lambda expressions are similar to anonymous functions in other languages. Lambda expressions are open formulas which also specify variables which are to be bound. Evaluation (finding the value of a function call) is then achieved by substituting the bound variables in the lambda expression's body, ...

The [RegularExpression] attribute can decorate any properties or public fields and specifies a regular expression that must be matched for the property be considered valid. [RegularExpression(validationExpression)] public string Property { get; set; } Additionally, it accepts an optional ErrorM...

In order to use compression over the wire for a faster transfer, pass the --compress option to mysqldump. Example: mysqldump -h db.example.com -u username -p --compress dbname > dbname.sql Important: If you don't want to lock up the source db, you should also include --lock-tables=false. But ...

gunzip -c dbname.sql.gz | mysql dbname -u username -p Note: -c means write output to stdout.

Available in Git 1.8.2 and above. 1.8 Pre-push hooks can be used to prevent a push from going though. Reasons this is helpful include: blocking accidental manual pushes to specific branches, or blocking pushes if an established check fails (unit tests, syntax). A pre-push hook is created by simpl...

Using the same example as Evaluating a NodeList in an XML document, here is how you would make multiple XPath calls efficiently: Given the following XML document: <documentation> <tags> <tag name="Java"> <topic name="Regular expression...

In this case, you want to have the expression compiled before the evaluations, so that each call to evaluate does not compile the same expression. The simple syntax would be: XPath xPath = XPathFactory.newInstance().newXPath(); //Make new XPath XPathExpression exp = xPath.compile("/documentat...

Let's see MVP in action using a simple Login Screen. There are two Buttons—one for login action and another for a registration screen; two EditTexts—one for the email and the other for the password. LoginFragment (The View) public class LoginFragment extends Fragment implements LoginContract.Prese...

Demonstrate how to embed a lua interpreter in C code, expose a C-defined function to Lua script, evaluate a Lua script, call a C-defined function from Lua, and call a Lua-defined function from C (the host). In this example, we want the mood to be set by a Lua script. Here is mood.lua: -- Get versi...

Considering a (post)model: public class User { public string FirstName { get; set; } public bool IsAdmin { get; set; } } With a view like so: @using (Html.BeginForm()) { @Html.EditorFor(model => model.FirstName) <input type="submit" value="Save" /...

There are two possible ways of including LaTeX preamble commands (e.g. \usepackage) in a RMarkdown document. 1. Using the YAML option header-includes: --- title: "Including LaTeX Preample Commands in RMarkdown" header-includes: - \renewcommand{\familydefault}{cmss} - \usepacka...

Most websites require a much more complicated process than the one demonstrated above. Common steps for logging into a website are: Get the unique cookie from the initial login form. Inspect the login form to see what the destination url is for the authentication request Parse the login form t...

If you wish to make a complete backup of a large MySql installation and do not have sufficient local storage, you can dump and compress it directly to an Amazon S3 bucket. It's also a good practice to do this without having the DB password as part of the command: mysqldump -u root -p --host=localho...

Immediately invoked function expressions can be used to create a private scope while producing a public API. var Module = (function() { var privateData = 1; return { getPrivateData: function() { return privateData; } }; })(); Module.getPrivateData(); // 1 Module.priva...

Add the gradle dependency in app-level build.gradle compile 'com.android.volley:volley:1.0.0' Also, add the android.permission.INTERNET permission to your app's manifest. **Create Volley RequestQueue instance singleton in your Application ** public class InitApplication extends Application { ...

GROUP BY clause groups rows by some value: SELECT type, count(*) as c FROM sys.objects GROUP BY type You can apply some function on each group (aggregate function) to calculate sum or count of the records in the group. typecSQ3S72IT16PK1U5

BackAndroid.addEventListener('hardwareBackPress', function() { if (!this.onMainScreen()) { this.goBack(); return true; } return false; }); Note: this.onMainScreen() and this.goBack() are not built in functions, you also need to implement those. (https://github.c...

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 ...