Tutorial by Examples: g

If you want to get rid of the username field and use email as unique user identifier, you will have to create a custom User model extending AbstractBaseUser instead of AbstractUser. Indeed, username and email are defined in AbstractUser and you can't override them. This means you will also have to r...

Below you could find the table Employees with a reference to the table Cities. CREATE TABLE Cities( CityID INT IDENTITY(1,1) NOT NULL, Name VARCHAR(20) NOT NULL, Zip VARCHAR(10) NOT NULL ); CREATE TABLE Employees( EmployeeID INT IDENTITY (1,1) NOT NULL, FirstName VARCHA...

You can specify a column that contains dates so pandas would automatically parse them when reading from the csv pandas.read_csv('data_file.csv', parse_dates=['date_column'])

Read text file from path: val sc: org.apache.spark.SparkContext = ??? sc.textFile(path="/path/to/input/file") Read files using wildcards: sc.textFile(path="/path/to/*/*") Read files specifying minimum number of partitions: sc.textFile(path="/path/to/input/file&qu...

C# has several operators that can be combined with an = sign to evaluate the result of the operator and then assign the result to the original variable. Example: x += y is the same as x = x + y Assignment operators: += -= *= /= %= &= |= ^= <<= >>=

This example demonstrates that HTTP is a text-based Internet communications protocol, and shows a basic HTTP request and the corresponding HTTP response. You can use Telnet to manually send a minimal HTTP request from the command line, as follows. Start a Telnet session to the web server www.e...

In the HTTP server code (e.g. server.js): const EventEmitter = require('events') const serverEvents = new EventEmitter() // Set up an HTTP server const http = require('http') const httpServer = http.createServer((request, response) => { // Handler the request... // Then emit an event...

Objective-C NSMutableAttributedString *attributeString = [[NSMutableAttributedString alloc] initWithString:@"Your String here"]; [attributeString addAttribute:NSStrikethroughStyleAttributeName value:@2 range:NSMakeRange(0, [attributeString length...

/* This is a CSS comment */ div { color: red; /* This is a CSS comment */ }

{ "some_string": null, "ather_string": "something" } If we will use this way: JSONObject json = new JSONObject(jsonStr); String someString = json.optString("some_string"); We will have output: someString = "null"; So we need to...

A <clip-path> defines a shape which acts as a window, only allowing parts of a <path> to show if they are within the <clip-path> shape and cutting off the rest. <vector xmlns:android="http://schemas.android.com/apk/res/android" xmlns:tools="http://schemas.an...

A <group> tag allows the scaling, rotation, and position of one or more elements of a VectorDrawable to be adjusted: <vector xmlns:android="http://schemas.android.com/apk/res/android" android:width="24dp" android:height="24dp" android:viewportWidth="24...

The s interpolator allows the usage of variables within a string. val name = "Brian" println(s"Hello $name") prints "Hello Brian" to the console when ran.

Given the following CSV file: Id,Name 1,"Joel" 2,"Adam" 3,"Ryan" 4,"Matt" You can read the data with the following script: #r "FSharp.Data.dll" open FSharp.Data type PeopleDB = CsvProvider<"people.csv"> let people = Pe...

BEGIN UPDATE Employees SET PhoneNumber = '5551234567' WHERE Id = 1; UPDATE Employees SET Salary = 650 WHERE Id = 3; END

String concatenation can be performed using the + operator. For example: String s1 = "a"; String s2 = "b"; String s3 = "c"; String s = s1 + s2 + s3; // abc Normally a compiler implementation will perform the above concatenation using methods involving a StringBui...

0.18.0 Prior to 0.18.0 you can create ranges like this: > range = [1..5] [1,2,3,4,5] : List number > > negative = [-5..3] [-5,-4,-3,-2,-1,0,1,2,3] : List number 0.18.0 In 0.18.0 The [1..5] syntax has been removed. > range = List.range 1 5 [1,2,3,4,5] : List number > &g...

> listOfNumbers = [1,4,99] [1,4,99] : List number > > listOfStrings = ["Hello","World"] ["Hello","World"] : List String > > emptyList = [] -- can be anything, we don't know yet [] : List a > Under the hood, List (linked list) is ...

> ourList = [1,2,3,4,5] [1,2,3,4,5] : List number > > firstElement = List.head ourList Just 1 : Maybe Int > > allButFirst = List.tail ourList Just [2,3,4,5] : Maybe (List Int) This wrapping into Maybe type happens because of the following scenario: What should List.head ret...

List.map : (a -> b) -> List a -> List b is a higher-order function that applies a one-parameter function to each element of a list, returning a new list with the modified values. import String ourList : List String ourList = ["wubba", "lubba", "dub",...