Tutorial by Examples: p

This is very common, you memorize a path to a file or folder, you open up Vim and try to write what you've just memorized, but you are not 100% sure it's correct, so you close the editor and start over. When you want the path completion feature, and you have a file /home/ubuntu/my_folder/my_file a...

:s/foo/bar Replace the first instance of foo with bar on the current line. :s/foo/bar/g Replace every instance of foo with bar on the current line. :%s/foo/bar/g Replace foo with bar throughout the entire file.

Apart from the built-in colormaps defined in the colormaps reference (and their reversed maps, with '_r' appended to their name), custom colormaps can also be defined. The key is the matplotlib.cm module. The below example defines a very simple colormap using cm.register_cmap, containing a single c...

The original default colourmap of MATLAB (replaced in version R2014b) called jet is ubiquitous due to its high contrast and familiarity (and was the default of matplotlib for compatibility reasons). Despite its popularity, traditional colormaps often have deficiencies when it comes to representing d...

We have a Product model and we want to group them by their category. Product.select(:category).group(:category) This will query the database as follows: SELECT "product"."category" FROM "product" GROUP BY "product"."category" Make sure that t...

The getopts builtin can be used inside functions to write functions that accommodate flags and optional parameters. This presents no special difficulty but one has to handle appropriately the values touched by getopts. As an example, we define a failwith function that writes a message on stderr an...

Install the stable release from CRAN: install.packages("data.table") Or the development version from github: install.packages("data.table", type = "source", repos = "http://Rdatatable.github.io/data.table") To revert from devel to CRAN, the ...

This example will show how to get the mouse position relative to the canvas, such that (0,0) will be the top-left hand corner of the HTML5 Canvas. The e.clientX and e.clientY will get the mouse positions relative to the top of the document, to change this to be based on the top of the canvas we subt...

As the Clang front-end is designed for being compatible with GCC, most programs that can be compiled via GCC will compile when you swap g++ by clang++ in the build scripts. If no -std=version is given, gnu11 will be used. Windows users who are used to MSVC can swap cl.exe with clang-cl.exe. By defa...

If you want to detect when your user starts or finishes an activity such as walking, running, or any other activity of the DetectedActivityFence class, you can create a fence for the activity that you want to detect, and get notified when your user starts/finishes this activity. By using a Broadcast...

It is always recommend to go to the LLVM official website and follow the installation guides depending on your OS. If you are working on posix then in short you have to add one of the official LLVM package repositories. For example if you work on Ubuntu Xenial (16.04) you add a deb and deb-src entr...

There are currently three YouTube APIs available to the public: YouTube Data API YouTube Analytics API YouTube Reporting API Each of these offer different functionality and are treated as separate, individual APIs. Since YouTube is a subsidiary of Google, the various YouTube APIs are provid...

Macros are simple string replacements. (Strictly speaking, they work with preprocessing tokens, not arbitrary strings.) #include <stdio.h> #define SQUARE(x) x*x int main(void) { printf("%d\n", SQUARE(1+2)); return 0; } You may expect this code to print 9 (3*3), ...

DatePickerDialog is the simplest way to use DatePicker, because you can show dialog anywhere in your app. You don't have to implement your own layout with DatePicker widget. How to show dialog: DatePickerDialog datePickerDialog = new DatePickerDialog(context, listener, year, month, day); datePick...

DatePicker allows user to pick date. When we create new instance of DatePicker, we can set initial date. If we don't set initial date, current date will be set by default. We can show DatePicker to user by using DatePickerDialog or by creating our own layout with DatePicker widget. Also we can ...

Below are the PHP5 SuperGlobals $GLOBALS $_REQUEST $_GET $_POST $_FILES $_SERVER $_ENV $_COOKIE $_SESSION $GLOBALS: This SuperGlobal Variable is used for accessing globals variables. <?php $a = 10; function foo(){ echo $GLOBALS['a']; } //Which will print 10 Glo...

POST /token HTTP/1.1 Host: server.example.com Content-Type: application/x-www-form-urlencoded grant_type=password&username=[USERNAME]&password=[PASSWORD] &client_id=[APP_KEY]&client_secret=[APP_SECRET] Source

The normal obj.save() method will use the default database, or if a database router is used, it will use the database as specified in db_for_write. You can override it by using: obj.save(using='other_db') obj.delete(using='other_db') Similarly, for reading: MyModel.objects.using('other_db').al...

Roles also enable you to define other roles as a dependency by creating a meta/main.yml file with a dependencies block: dependencies: - role: common It's also possible to pass a value to a parameter/variable in the dependent role: dependencies: - { role: common, some_parameter: 3 } Or ...

class Digit { public Digit(double d) { val = d; } public double val; // User-defined conversion from Digit to double public static implicit operator double(Digit d) { Console.WriteLine("Digit to double implict conversion called"); return d.val;...