All Questions

While reading I found this expression:

_=$=+[],++_+''+$

Curiously, it is a valid expression in javascriptbut the most curious thing is that when it is executed, the result is:

10

I tried to make sense of it by breaking the expression down but I didn't get much done.

Why is the result of that expression equal to 10?

What is the meaning of; underscore, double underscore, etc? when naming objects in python?

When taking the values ​​of one <form ...>I found that I can store them in these two ways, user_post = ...or using self.user_post = ..., I would like to know what is the correct way to do it, or what is the difference between one and the other, in both ways the code works which is what stranger to me.

Without self:

class SignUpHandler(Handler):

    def get(self):
        self.render('signUp.html')

    def post(self):
        user_post = self.request.get('username')
        passwd_post = self.request.get('password')

With self:

class SignUpHandler(Handler):

    def get(self):
        self.render('signUp.html')

    def post(self):
        self.user_post = self.request.get('username')
        self.passwd_post = self.request.get('password')

I have a question and it is the following.

My goal is to replace the values ​​of all the fruits to increase the price by 5%:

// precios originales

$precios = array (

    "frutas" => array (

"manzanas" => 15,
"peras" => 5,
"naranjas" => 3,
),

"verduras" => array (
  "clave" => 15,
  "clave2" => 5,
  "clave3" => 3,
)

);

// Los precios de frutas suben 5%

foreach ($precios['frutas'] as $clave => $valor) {
  $nuevovalor = $valor*5/100+$valor;
  $valor = ceil($nuevovalor);
}

// los precios de las verduras suben un 3%
foreach ($precios['verduras'] as $clave => $valor) {
  $nuevovalor = $valor*3/100+$valor;
  $valor = ceil($nuevovalor);
}

My idea is to use the function array_replacebut so far, nothing I have done seems to work to replace the values ​​with the new prices, this in case the new prices are well resolved with that function, your idea will be welcome, greetings.

They gave me this code as homework, but I don't know how to run it, any help?

using System;

public class Example
{
   public static void Main(string[] args)
   {
      Console.WriteLine("Hello, World!");
      Console.WriteLine("You entered the following {0} command line arguments:",
         args.Length );
      for (i=0; i < args.Length; i++)
      {
         Console.WriteLine("{0}", args[i]); 
      }
   }
}