Skip to content

Tag: programming

half-hexagon in OpenSCAD

Published by Silveira on 2025-01-16 
height = 5;
radius = 20;

difference() {
  cylinder(height, radius, radius, $fn=6);
  translate([-radius, 0, -height/4]) {            
    cube([radius*2, radius, radius]);
  }
}

It works for these parameters but it needs more work to be really parametric. But hey, it’s my first OpenSCAD thing. I actually exported as .STL and printed it.

Chain of Promises Example

Published by Silveira on 2024-10-22 
const f1 = async() => {
    setTimeout( () => {
        console.log("f1");
    }, 100)
};

const f2 = async() => {
    setTimeout( () => {
        console.log("f2");
    }, 100)
};

const f3 = async() => {
    return new Promise((resolve, reject) => {
        reject("f3");
    });
};

const f4 = async() => {
    setTimeout( () => {
        console.log("f4");
    }, 100)
};

const workflow = async () => {
    await f1();
    await f2();
    await f3();
    await f4();
};

workflow().catch((error)=>{
    console.error(error);
})

conditional past, present, future in spreadsheets/Excel

Published by Silveira on 2023-06-27 
=IF(B2=TODAY(),"Past",IF(B2<TODAY(),"Today",TEXT(B2,"ddd")))
  • Given a column B that contains dates in a sequential order.
  • Shows a “Today” when it’s today.
  • Shows a “Past” when is past.
  • Shows an abbreviated name of the day of the week.

Here is an example using emojis instead of past/today:

Ruby super

Published by Silveira on 2022-10-04 
class A
   def foo 
      [1, 2, 3]
   end 
end

class B < A 
   def foo 
      super.map{ |n| n * 2 } 
   end 
end

puts A.new.foo.to_s
puts B.new.foo.to_s

Output

[1, 2, 3]
[2, 4, 6]

flatten directory structure

Published by Silveira on 2021-11-16

Move files in current subdirectories to the current directory.

find . -mindepth 2 -type f -exec mv -t . -i '{}' +

Delete local folders that are empty.

 find . -empty -type d -delete

Python: Getting page title

Published by Silveira on 2020-05-26 
# Get the HTML page content
from urllib import request
html = request.urlopen("https://silveiraneto.net").read()

# Get the title tag
from bs4 import BeautifulSoup
title = BeautifulSoup(html, 'html.parser').find('title')

print(title.string)

This uses the XML/HTML library BeautifulSoup . This could also be done using regex but playing with HTML and regex is usually a bad idea.

Cedilha no Ubuntu 16.04

Published by Silveira on 2017-03-05 
    çççç
  ççç  ççç 
  ççç  ççç 
  ççç 
  ççç 
  ççç  ççç 
    çççç
     çç
    çç

Fiz esse script (cedilha.sh) pra fazer o c-cedilha (ç) funcionar no Ubuntu 16.04. Como é uma tarefa chata que eu já tive que fazer muitas vezes fica mais fácil pra mim ter um script pra fazer isso e pode ser que seja útil a outras pessoas. Infelizmente é uma solução que exige baixar e executar como root um script da internet. Eu recomendo que você leia o script e entenda o que está acontecendo antes de executá-lo. Esse script altera vários arquivos importantes e ele faz um backup (.bak) desses arquivos.

[bash]wget https://raw.githubusercontent.com/silveira/cedilha.sh/master/cedilha.sh
sudo bash cedilha.sh[/bash]

Por favor, se o script funcionou pra você também, diga nos comentários. Se você não está usando Ubuntu 16.04 e quer testar o script ainda assim, edite o script e remova a verificação no inicio do programa.