Python - Run the next command without waiting for the end of the first

Question

Good evening, everyone.

I have the following function to create a bar Progress:

def progress_bar(p_value, p_max: int):
    """
    :70 = É o tamanho da barra
    :param p_value: Valor que está sendo iterado de um laço de repetição
    :param p_max: É a quantidade total do dados que está sendo iterado
    :return:
    """
    chars = int(p_value * 40 / float(p_max))
    percent = int((p_value / float(p_max)) * 100)
    sys.stdout.write("  ") + sys.stdout.write("#" * chars)
    sys.stdout.write(" " * (40 - chars + 2))
    if p_value >= p_max:
        sys.stdout.write("done. \n\n")
    else:
        sys.stdout.write("[%3i%%]\r" % percent)
        sys.stdout.flush()

Now I need to call it inside the loop below so that the bar is inside the frame created by the top and bottom print. The top print is fine, creates good, but the bottom one only creates after the loop is finished.

How do I make it all together and load the bar Progress inside the square?

is more for the sake of aesthetics.

print(" ╔════════════════════════════════════════════════════════════════════════════╗")
for i, item in enumerate(p_list):
    progress_bar(i + 1, len(p_list))
    print(" ║ " + item.ljust(75) + "║")
print(" ╚════════════════════════════════════════════════════════════════════════════╝")

Grateful for the support.

Answer 1

Note 1: I’ll assume your terminal supports ANSI.

Note 2: For simplicity’s sake, I’m not going to go into threads in that answer.

The function print Python (and most programming languages) receives a text and writes it in the terminal from left to right, from top to bottom (i.e., sequentially). In the case of your progress bar, you need to change this behavior so that you can manually enter the position of each character.

First of all, let’s create a function that clears the terminal screen. You didn’t say which operating system you are using, so it follows a portable function (Windows and Unix):

def limpar_tela():
    os.system('cls' if os.name == 'nt' else 'clear')

Now to the most important function: One print that receives the row and column.

def print_at(x, y, texto):
    print(f'\033[{y};{x}H{texto}')

Example: The call print_at(1, 1, 'G') will write a G in the first row and first column of your terminal (i.e., the top left corner).

Now a simple tie for allows you to create the progress bar. We can use the function time.sleep to simulate a short wait in order to view the filling progress bar.

limpar_tela()

print(" ╔════════════════════════════════════════════════════════════════════════════════════════════════════╗")
print(" ║                                                                                                    ║")
print(" ╚════════════════════════════════════════════════════════════════════════════════════════════════════╝")
print()
print(" Progresso: ")

for x in range(100):
    print_at(x + 3, 2, 'X')
    print_at(13, 5, f'{x + 1}%')
    time.sleep(0.03)

print()

Follow the full code:

import os
import time

def limpar_tela():
    os.system('cls' if os.name == 'nt' else 'clear')

def print_at(x, y, texto):
    print(f'\033[{y};{x}H{texto}')

def main():
    limpar_tela()

    print(" ╔════════════════════════════════════════════════════════════════════════════════════════════════════╗")
    print(" ║                                                                                                    ║")
    print(" ╚════════════════════════════════════════════════════════════════════════════════════════════════════╝")
    print()
    print(" Progresso: ")

    for x in range(100):
        print_at(x + 3, 2, 'X')
        print_at(13, 5, f'{x + 1}%')
        time.sleep(0.03)

    print()

if __name__ == '__main__':
    main()

Additional reading:

• https://docs.python.org/3/library/os.html#os.name
• https://docs.python.org/3/library/os.html#os.system
• https://docs.python.org/3/library/time.html#time.Sleep
• http://www.termsys.demon.co.uk/vtansi.htm