dodyg

This is a quick guide to Kotlin programming language. The previous part of this guide is here

#Object Oriented

fun main(args : Array<String>) {
  class local (val x : Int)
  
  val y = local(10)
 println("${y.x}")

dodyg

#Intro

Kotlin is a new programming language for the JVM. It produces Java bytecode, supports Android and generates JavaScript. The latest version of the language is Kotlin M5.3

Kotlin project website is at kotlin.jetbrains.org.

All the codes here can be copied and run on Kotlin online editor.

Let's get started.

dodyg

#Control Structures

##If statement

Kotlin if statement should look familiar with other language

fun main(args : Array<String>) {
 val total = 10

steveosoule

<?
$ftp_server = "ftp.domainname.com";
$ftp_user_name = "ftp_username";
$ftp_user_pass = "ftp_password";
$ftp_directory = 'path/to/folder/'; // leave blank
$ftp_source_file_name = "data.xml";
$ftp_dest_file_name = $ftp_source_file_name;

if( ftp_file( $ftp_server, $ftp_user_name, $ftp_user_pass, $ftp_source_file_name, $ftp_directory, $ftp_dest_file_name) ){
	echo "Success: FTP'd data\n";

simonw

from django.http import HttpResponse

PIXEL_GIF_DATA = """
R0lGODlhAQABAIAAAAAAAP///yH5BAEAAAAALAAAAAABAAEAAAIBRAA7
""".strip().decode('base64')

def pixel_gif(request):
    return HttpResponse(PIXEL_GIF_DATA, content_type='image/gif')

Kartones

PSQL

Magic words:

psql -U postgres

Some interesting flags (to see all, use -h or --help depending on your psql version):

• -E: will describe the underlaying queries of the \ commands (cool for learning!)
• -l: psql will list all databases and then exit (useful if the user you connect with doesn't has a default database, like at AWS RDS)

bsweger

Useful Pandas Snippets

A personal diary of DataFrame munging over the years.

Data Types and Conversion

Convert Series datatype to numeric (will error if column has non-numeric values)
(h/t @makmanalp)

p3t3r67x0

openssl

Install

Install the OpenSSL on Debian based systems

sudo apt-get install openssl

regisdiogo

public class Startup
{
  public IServiceProvider ConfigureServices(IServiceCollection services)
  {
    services.AddMvc().AddJsonOptions(options =>
    {
      options.SerializerSettings.Converters.Add(new Newtonsoft.Json.Converters.StringEnumConverter());
      options.SerializerSettings.NullValueHandling = Newtonsoft.Json.NullValueHandling.Ignore;
    });
  }

victorono

from django.db.models import Count, Max

unique_fields = ['field_1', 'field_2']

duplicates = (
    MyModel.objects.values(*unique_fields)
    .order_by()
    .annotate(max_id=Max('id'), count_id=Count('id'))
    .filter(count_id__gt=1)
)