[Tut] How to Display a Progress Bar in Python

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How to Display a Progress Bar in Python

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Problem Formulation and Solution Overview

In this article, you’ll learn how to configure and display a progress bar.

A progress bar is commonly used in Python or, for that matter, any other programming language to show the user an application’s progress. For example, an installation, a transferring of files, or any other commands.

The Finxter Academy recommends implementing this to visually display to the user what is happening behind the scenes.

Question: How would we write code to display a progress bar?

We can accomplish this task by one of the following options:

• Method 1: Use a
  Code:

  for
  loop
  
  
• Method 2: Use
  Code:

  apytl
  library
  Code:

  Bar().drawbar()
  function
  
  
• Method 3: Use
  Code:

  alive-progress
  
  
  
• Method 4: Use
  Code:

  tqdm
  
  
  
• Method 5: Use
  Code:

  progress
  
  

Method 1: Use a For Loop



This method imports the

Code:

time

and

Code:

sys

libraries combined with a

Code:

for

loop to display a custom progress bar output on a single line.

Code:

from time import sleep import sys for x in range(0,21): sys.stdout.write('\r') sys.stdout.write("[%-20s] %d%%" % (''*x, 5*x)) sys.stdout.flush() sleep(0.75)

Above imports, the

Code:

time

library to call the sleep command and the

Code:

sys

library to write the contents to the terminal.

Next, a

Code:

for

loop is instantiated. This loop uses the

Code:

range

function to set the start position (0 by default) and the stop position (21-1). Inside this loop, the following occurs:

• The first line uses a carriage return (
  Code:

  \r
  ) to start the code on a new line.
  
  
• The following line determines how the progress bar appears by:
  • Left-aligning the emoji(s) inside the square brackets
    Code:

    [%-20s]
    .
    
    
  • Configuring the progress percentage
    Code:

    %d%%" %
    (example
    Code:

    15%
    ).
    
    
  • Determining the visual emoji progress
    Code:

    (':beaming_face_with_smiling_eyes:'*x, 5*x)
    .
    
  
  
• Then
  Code:

  sys.stdout.flush()
  writes everything in the buffer to the terminal.
  
  
• The code pauses for the stated period (
  Code:

  0.75
  ).
  

The loop continues until 100% has been attained. Below is the end result.

[] 100%

Note: Any emoji or another symbol can be substituted for the above selection.

Method 2: Use apytl Library

This method imports the

Code:

time

and

Code:

apytl

libraries to generate a custom progress bar.

To run this code error-free, install the required library. Click here for installation instructions.

Code:

import time import apytl total_iterations = 10 for index, value in enumerate(range(total_iterations)): apytl.Bar().drawbar(value, total_iterations, fill='*') time.sleep(0.75)

Above imports the

Code:

time

library to call the sleep command and the

Code:

apytl

library to display the progress bar.

Next, the total number of iterations to carry out is declared as

Code:

10

and saved to

Code:

total_iterations

.

To understand what is going on in the

Code:

for

loop, let’s write some test code to see what the values of

Code:

index

,

Code:

value

and

Code:

total_iterations

are doing:

Code:

total_iterations = 10 for index, value in enumerate(range(total_iterations)): print(index, value, total_iterations)

As you can see from the output, the

Code:

index

and

Code:

value

variables count from 0 (

Code:

range

default start position) to the stop position of 9 (10-1). Notice the value of

Code:

total_iterations

does not change.

Code:

0 0 101 1 102 2 103 3 104 4 105 5 106 6 107 7 108 8 109 9 10

Referring back to the code directly below the Method 2 heading, the next line is:

Code:

apytl.Bar().drawbar(value, total_iterations, fill='*')

.

This function is passed three (3) arguments:

• The variable
  Code:

  value
  , which you can see from the above, increments by one (1) each iteration.
  
  
• The variable
  Code:

  total_iterations
  , which remains constant at
  Code:

  10
  .
  
  
• The fill value. This example uses the asterisk (
  Code:

  *
  ) character. However, feel free to use an emoji or other symbol.
  

Progress |***********************************| 100.0% Complete

Method 3: Use alive-progress

The

Code:

alive-progress

library moves progress bars to the next level! With its many display options, it’s a must-a-try!

To run this code error-free, install the required library. Click here for installation instructions.

Code:

from alive_progress import alive_bar from time import sleep for x in range(10): with alive_bar(x, bar='solid') as bar: for i in range(x): sleep(.001) bar()

Above imports the

Code:

alive-progress

library to use the progress bar and the

Code:

time

library to call the

Code:

sleep

command.

Next, a

Code:

for

loop is instantiated. This loop uses the

Code:

range

function to set the stop position at 9 (10-1). Inside this loop, the following occurs:

• The
  Code:

  alive_bar
  is called and passed the argument
  Code:

  x
  and the bar type. For this example,
  Code:

  solid
  was selected.
  • A new
    Code:

    for
    loop is instantiated and loops through
    Code:

    range
    passing
    Code:

    x
    as an argument.
    
    
  • The code halts (
    Code:

    sleep
    ) for the stated period (
    Code:

    .001
    ).
    
    
  • The bar is output to the terminal each iteration.
    

The loop continues until 100% has been attained.

<■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■> 0 in 0.0s (0.00/s)
<■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■> 1/1 [100%] in 0.0s (333.28/s)
<■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■> 2/2 [100%] in 0.0s (62.48/s)
<■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■> 3/3 [100%] in 0.0s (63.96/s)
<■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■> 4/4 [100%] in 0.1s (62.39/s)
<■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■> 5/5 [100%] in 0.1s (63.32/s)
<■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■> 6/6 [100%] in 0.1s (64.84/s)
<■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■> 7/7 [100%] in 0.1s (63.79/s)
<■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■> 8/8 [100%] in 0.1s (63.53/s)
<■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■> 9/9 [100%] in 0.1s (64.09/s)

Note: To view a list of all available progress bars, click here.

Method 4: Use tqdm

A simple yet elegant progress bar,

Code:

tqdm

is a must-see!

To run this code error-free, install the required library. Clickhttps://pypi.org/project/alive-progress/1.0/here for installation instructions.

Code:

from tqdm import tqdm from time import sleep for i in tqdm(range(100)): sleep(0.02)

Above imports the

Code:

tqdm

library for the progress bar and the

Code:

time

library to call the

Code:

sleep()

command.

Next, a

Code:

for

loop is instantiated. This loop uses the

Code:

tqdm

library with the

Code:

range

function to set the stop position at 99 (100-1). Inside this loop, the following occurs:

The progress bar displays on one line. Each iteration increases the progress by a percentage.



Method 5: Use progress Library

This method uses the

Code:

progress

library to display a progress bar. This library has many fun options to select from.

To run this code error-free, install the required library. Clickhttps://pypi.org/project/tqdm/here for installation instructions.

Code:

from time import sleep from progress.spinner import MoonSpinner with MoonSpinner('Processing…') as bar: for i in range(100): sleep(0.02) bar.next()

Above imports the

Code:

time

library to call the sleep command and thehttps://pypi.org/project/apytl/

Code:

progress

library to display a progress bar, specifically the

Code:

MoonSpinner

.

The following code displays the word

Code:

Processing...

at the terminal, and the

Code:

MoonSpinner

rotates, sleeps, and continues until the value of the

Code:

range

stop position (100-1) is attained.

Processing…◑

Note: Spend some time on this library page to test the different types of progress bars.

Summary

There is so much more to Python Progress Bars than was covered in this article. May we suggest you take time to delve into each method outlined above to determine the best one for your requirements.

Happy Coding!

Programming Humor – Python

[i]“I wrote 20 short programs in Python yesterday. It was wonderful. Perl, I’m leaving you.” — xkcd[/i]