Tutorial by Examples: re

Sample Data: CREATE TABLE table_name ( id, list ) AS SELECT 1, 'a,b,c,d' FROM DUAL UNION ALL -- Multiple items in the list SELECT 2, 'e' FROM DUAL UNION ALL -- Single item in the list SELECT 3, NULL FROM DUAL UNION ALL -- NULL list SELECT 4, 'f,,g' FROM DUAL; -- NULL item...

You can implement the swipe-to-dismiss and drag-and-drop features with the RecyclerView without using 3rd party libraries. Just use the ItemTouchHelper class included in the RecyclerView support library. Instantiate the ItemTouchHelper with the SimpleCallback callback and depending on which functi...

using System.Net; using System.IO; ... string requestUrl = "https://www.example.com/submit.html"; HttpWebRequest request = HttpWebRequest.CreateHttp(requestUrl); request.Method = "POST"; // Optionally, set properties of the HttpWebRequest, such as: request.AutomaticD...

using System.Net; using System.IO; ... string requestUrl = "https://www.example.com/page.html"; HttpWebRequest request = HttpWebRequest.CreateHttp(requestUrl); // Optionally, set properties of the HttpWebRequest, such as: request.AutomaticDecompression = DecompressionMethods.GZ...

using System.Net; ... string serverResponse; try { // Call a method that performs an HTTP request (per the above examples). serverResponse = PerformHttpRequest(); } catch (WebException ex) { if (ex.Status == WebExceptionStatus.ProtocolError) { HttpWebResponse...

Common table expressions support extracting portions of larger queries. For example: WITH sales AS ( SELECT orders.ordered_at, orders.user_id, SUM(orders.amount) AS total FROM orders GROUP BY orders.ordered_at, orders.user_id ) SELECT sales.ordered_at, sales.total,...

Two Random class created at the same time will have the same seed value. Using System.Guid.NewGuid().GetHashCode() can get a different seed even in the same time. Random rnd1 = new Random(); Random rnd2 = new Random(); Console.WriteLine("First 5 random number in rnd1"); for (int i = 0...

Average The AVG() aggregate function will return the average of values selected. SELECT AVG(Salary) FROM Employees Aggregate functions can also be combined with the where clause. SELECT AVG(Salary) FROM Employees where DepartmentId = 1 Aggregate functions can also be combined with group by ...

This query selects all employees not on the Supervisors table. SELECT * FROM Employees WHERE EmployeeID not in (SELECT EmployeeID FROM Supervisors) The same results can be achieved using a LEFT JOIN. SELECT * FROM Employees AS e LEFT JOIN Supervisors AS s ON s.E...

We can use jasmine.createSpy() to create a standalone spy. This is often useful if we need to pass a function as a callback to another function and want to test how it is used. // source code function each(arr, fn) { arr.forEach(fn); } // test code describe('each', function() { let m...

The NSDate class provides methods for creating NSDate objects corresponding to a given date and time. An NSDate can be initialized using the designated initializer, which: Returns an NSDate object initialized relative to 00:00:00 UTC on 1 January 2001 by a given number of seconds. NSDate *date...

The procedure describes how to add an Object library reference, and afterwards how to declare new variables with reference to the new library class objects. The example below shows how to add the PowerPoint library to the existing VB Project. As can be seen, currently the PowerPoint Object library...

Large Multi-Line strings are burdensome to write. my $variable = <<'EOF'; this block of text is interpreted literally, no \'quotes matter, they're just text only the trailing left-aligned EOF matters. EOF NB: Make sure you ignore stack-overflows syntax highlighter: It is very wrong. A...

import pandas as pd import io temp=u"""index; header1; header2; header3 1; str_data; 12; 1.4 3; str_data; 22; 42.33 4; str_data; 2; 3.44 2; str_data; 43; 43.34 7; str_data; 25; 23.32""" #after testing replace io.StringIO(temp) to filename df = pd.read_csv(io....

Analog to get a collection for a Stream by collect() an array can be obtained by the Stream.toArray() method: List<String> fruits = Arrays.asList("apple", "banana", "pear", "kiwi", "orange"); String[] filteredFruits = fruits.stream() ....

A common pitfall of child classes is that, if your parent and child both contain a constructor(__construct()) method, only the child class constructor will run. There may be occasions where you need to run the parent __construct() method from it's child. If you need to do that, then you will need to...

To support a given application, you often create a new role and database to match. The shell commands to run would be these: $ createuser -P blogger Enter password for the new role: ******** Enter it again: ******** $ createdb -O blogger blogger This assumes that pg_hba.conf has been prope...

Table file with header, footer, row names, and index column: file: table.txt This is a header that discusses the table file to show space in a generic table file index name occupation 1 Alice Salesman 2 Bob Engineer 3 Charlie Janitor This is a footer becaus...

Introduction The BufferedReader class is a wrapper for other Reader classes that serves two main purposes: A BufferedReader provides buffering for the wrapped Reader. This allows an application to read characters one at a time without undue I/O overheads. A BufferedReader provides functi...

An array of strings can mean a couple of things: An array whose elements are char *s An array whose elements are arrays of chars We can create an array of character pointers like so: char * string_array[] = { "foo", "bar", "baz" }; Remember: w...