Tutorial by Examples: f

To delete all rows from the table //get writable database SQLiteDatabase db = openHelper.getWritableDatabase(); db.delete(TABLE_NAME, null, null); db.close(); To delete all rows from the table and get the count of the deleted row in return value //get writable database SQLiteDatabase db =...

Download your preferred version from Lightbend with curl: curl -O http://downloads.lightbend.com/scala/2.xx.x/scala-2.xx.x.tgz Unzip the tar file to /usr/local/share or /opt/bin: unzip scala-2.xx.x.tgz mv scala-2.xx.x /usr/local/share/scala Add the PATH to ~/.profile or ~/.bash_profile or ...

Case classes provide a copy method that creates a new object that shares the same fields as the old one, with certain changes. We can use this feature to create a new object from a previous one that has some of the same characteristics. This simple case class to demonstrates this feature: case cla...

The idea behind programming to an interface is to base the code primarily on interfaces and only use concrete classes at the time of instantiation. In this context, good code dealing with e.g. Java collections will look something like this (not that the method itself is of any use at all, just illus...

{ "description": "My awesome library", "dependencies": { }, "frameworks": { "net40": { }, "netstandard1.3": { "dependencies": { "NETStandard.Library": "1.6.0" ...

The special symbol T represents the value true in Common Lisp, while the special symbol NIL represents false: CL-USER> (= 3 3) T CL-USER> (= 3 4) NIL They are called “Constant Variables” (sic!) in the standard, since they are variables whose value cannot be modified. As a consequence, y...

R has a number of build in constants. The following constants are available: LETTERS: the 26 upper-case letters of the Roman alphabet letters: the 26 lower-case letters of the Roman alphabet month.abb: the three-letter abbreviations for the English month names month.name: the English names fo...

Any ASCII editor can edit batch files. A list of editors that can syntax highlight batch syntax can be found here. You can also use the default notepad shipped with windows to edit and view a batch file, although it does not offer syntax highlighting. To open notepad: Press Win 𐌎+R, type notepa...

I have the following list: 1. Alon Cohen 2. Elad Yaron 3. Yaron Amrani 4. Yogev Yaron I want to select the first name of the guys with the Yaron surname. Since I don't care about what number it is I'll just put it as whatever digit it is and a matching dot and space after it from the beginni...

Cache-Control: public, max-age=31536000 public means the response is the same for all users (it does not contain any personalized information). max-age is in seconds from now. 31536000 = 60 * 60 * 24 * 365. This is recommended for static assets that are never meant to change.

Cache-Control: private, max-age=60 private specifies that the response can be cached only for user who requested the resource, and can't be reused when other users request the same resource. This is appropriate for responses that depend on cookies.

Cache-Control: no-cache The client will behave as if the response was not cached. This is appropriate for resources that can unpredictably change at any time, and which users must always see in the latest version. Responses with no-cache will be slower (high latency) due to need to contact the s...

DateTime date = new DateTime(2016, 07, 06, 18, 30, 14); // Format: year, month, day hours, minutes, seconds Console.Write(String.Format("{0:dd}",date)); //Format by Culture info String.Format(new System.Globalization.CultureInfo("mn-MN"),"{0:dddd}",date); 6....

Fabric is a Python (2.5-2.7) library and command-line tool for streamlining the use of SSH for application deployment or systems administration tasks. It lets you execute arbitrary Python functions via the command line. Install fabric via pip install fabric Create fabfile.py in your root directory...

foldMap maps each element of the Foldable structure to a Monoid, and then combines them into a single value. foldMap and foldr can be defined in terms of one another, which means that instances of Foldable need only give a definition for one of them. class Foldable t where foldMap :: Monoid m...

As parameters (float, double) Floats are 32 bits in size, they are passed naturally on the stack. Doubles are 64 bits in size, they are passed, on the stack, respecting the Little Endian convention1, pushing first the upper 32 bits and than the lower ones. //C prototype of callee double foo(dou...

Python provides functions for justifying strings, enabling text padding to make aligning various strings much easier. Below is an example of str.ljust and str.rjust: interstates_lengths = { 5: (1381, 2222), 19: (63, 102), 40: (2555, 4112), 93: (189,305), } for road, length in...

This is a very common workflow when using Ansible for provisioning an AWS EC2 instance. This post assumes a basic understand of Ansible and most importantly, assumes you've properly configured it to connect to AWS. As Ansible official documentation insists, we are going to use four roles: 1- ami_f...

Managing AWS resources that scale up and down runs into the limits of the static inventory host file, that's why we need something dynamic. And that's what the dynamic inventories are for. Let's start: Download these ec2.ini and ec2.py files to the your project folder: cd my_ansible_project wget...

There is a maximum capacity an integer can store. And when you go over that limit, it will loop back to the negative side. For int, it is 2147483647 int x = int.MaxValue; //MaxValue is 2147483647 x = unchecked(x + 1); //make operation explicitly unchecked so that the ...