Python to print out status bar and percentage

Each Answer to this Q is separated by one/two green lines.

To implement a status bar like below:

[==========                ]  45%
[================          ]  60%
[==========================] 100%

I want to this to be printed out to stdout, and keep refreshing it, not print to another line. How to do this?

The '\r' character (carriage return) resets the cursor to the beginning of the line and allows you to write over what was previously on the line.

from time import sleep
import sys

for i in range(21):
    sys.stdout.write('\r')
    # the exact output you're looking for:
    sys.stdout.write("[%-20s] %d%%" % ('='*i, 5*i))
    sys.stdout.flush()
    sleep(0.25)

I’m not 100% sure if this is completely portable across all systems, but it works on Linux and OSX at the least.

There’s a Python module that you can get from PyPI called progressbar that implements such functionality. If you don’t mind adding a dependency, it’s a good solution. Otherwise, go with one of the other answers.

A simple example of how to use it:

import progressbar
from time import sleep
bar = progressbar.ProgressBar(maxval=20, \
    widgets=[progressbar.Bar('=', '[', ']'), ' ', progressbar.Percentage()])
bar.start()
for i in xrange(20):
    bar.update(i+1)
    sleep(0.1)
bar.finish()

To install it, you can use easy_install progressbar, or pip install progressbar if you prefer pip.

I found useful library tqdm (https://github.com/tqdm/tqdm/, previously: https://github.com/noamraph/tqdm). It automatically estimates time of completion and can be used as iterator.

Usage:

import tqdm
import time

for i in tqdm.tqdm(range(1000)):
    time.sleep(0.01)
    # or other long operations

Results in:

|####------| 450/1000  45% [elapsed: 00:04 left: 00:05, 99.15 iters/sec]

tqdm can wrap any iterable.

You can use \r (carriage return). Demo:

import sys
total = 10000000
point = total / 100
increment = total / 20
for i in xrange(total):
    if(i % (5 * point) == 0):
        sys.stdout.write("\r[" + "=" * (i / increment) +  " " * ((total - i)/ increment) + "]" +  str(i / point) + "%")
        sys.stdout.flush()

Here you can use following code as a function:

def drawProgressBar(percent, barLen = 20):
    sys.stdout.write("\r")
    progress = ""
    for i in range(barLen):
        if i < int(barLen * percent):
            progress += "="
        else:
            progress += " "
    sys.stdout.write("[ %s ] %.2f%%" % (progress, percent * 100))
    sys.stdout.flush()

With use of .format:

def drawProgressBar(percent, barLen = 20):
    # percent float from 0 to 1. 
    sys.stdout.write("\r")
    sys.stdout.write("[{:<{}}] {:.0f}%".format("=" * int(barLen * percent), barLen, percent * 100))
    sys.stdout.flush()

Further improving, using a function as :

import sys

def printProgressBar(i,max,postText):
    n_bar =10 #size of progress bar
    j= i/max
    sys.stdout.write('\r')
    sys.stdout.write(f"[{'=' * int(n_bar * j):{n_bar}s}] {int(100 * j)}%  {postText}")
    sys.stdout.flush()

calling example:

total=33
for i in range(total):
    printProgressBar(i,total,"blah")
    sleep(0.05)  

output:

[================================================  ] 96%  blah  

based on the above answers and other similar questions about CLI progress bar, I think I got a general common answer to all of them. Check it at https://stackoverflow.com/a/15860757/2254146

Here is a copy of the function, but modified to fit your style:

import time, sys

# update_progress() : Displays or updates a console progress bar
## Accepts a float between 0 and 1. Any int will be converted to a float.
## A value under 0 represents a 'halt'.
## A value at 1 or bigger represents 100%
def update_progress(progress):
    barLength = 20 # Modify this to change the length of the progress bar
    status = ""
    if isinstance(progress, int):
        progress = float(progress)
    if not isinstance(progress, float):
        progress = 0
        status = "error: progress var must be float\r\n"
    if progress < 0:
        progress = 0
        status = "Halt...\r\n"
    if progress >= 1:
        progress = 1
        status = "Done...\r\n"
    block = int(round(barLength*progress))
    text = "\rPercent: [{0}] {1}% {2}".format( "="*block + " "*(barLength-block), progress*100, status)
    sys.stdout.write(text)
    sys.stdout.flush()

Looks like

Percent: [====================] 99.0%

If you are developing a command line interface, I suggest you to take a look at click which is very nice:

import click
import time

for filename in range(3):
    with click.progressbar(range(100), fill_char="=", empty_char=" ") as bar:
        for user in bar:
            time.sleep(0.01)

Here the output you get:

$ python test.py
  [====================================]  100%
  [====================================]  100%
  [=========                           ]   27%

As described in Mark Rushakoff’s solution, you can output the carriage return character, sys.stdout.write('\r'), to reset the cursor to the beginning of the line. To generalize that solution, while also implementing Python 3’s f-Strings, you could use

from time import sleep
import sys

n_bar = 50
iterable = range(33)  # for demo purposes
n_iter = len(iterable)
for i, item in enumerate(iterable):
    j = (i + 1) / n_iter

    sys.stdout.write('\r')
    sys.stdout.write(f"[{'=' * int(n_bar * j):{n_bar}s}] {int(100 * j)}%")
    sys.stdout.flush()

    sleep(0.05)  
    # do something with <item> here

def printProgressBar(value,label):
    n_bar = 40 #size of progress bar
    max = 100
    j= value/max
    sys.stdout.write('\r')
    bar="?" * int(n_bar * j)
    bar = bar + '-' * int(n_bar * (1-j))

    sys.stdout.write(f"{label.ljust(10)} | [{bar:{n_bar}s}] {int(100 * j)}% ")
    sys.stdout.flush()

call:

printProgressBar(30,"IP")

IP | [????????????—————————-] 30%

I came upon this thread today and after having tried out this solution from Mark Rushakoff

from time import sleep
import sys

for i in range(21):
sys.stdout.write('\r')
# the exact output you're looking for:
sys.stdout.write("[%-20s] %d%%" % ('='*i, 5*i))
sys.stdout.flush()
sleep(0.25)

I can say that this works fine on W7-64 with python 3.4.3 64-bit but only in the native console. However when using the built-in console of spyder 3.0.0dev, the line breaks are still/again present. As this took me some time to figure out, I’d like to report this observation here.

Easiest is still

import sys
total_records = 1000
for i in range (total_records):
    sys.stdout.write('\rUpdated record: ' + str(i) + ' of ' + str(total_records))
    sys.stdout.flush()

Key is to convert the integer type to string.

enter image description here

None of the answers posted completely addressed my needs. So I wrote my own as shown above. The features I needed:

  • Pass only the step number and total number of steps and it does the difficult job of calculating percentage complete.
  • Using 60 characters, divide them into 480 “ticks” to yield 0.21 % per tick. Without ticks, each character would only be 1.67 %.
  • Support for prepending a title.
  • Optional percentage complete at end of line.
  • Variable length progress bar that defaults to 60 characters or 480 “ticks”.
  • Set progress bar color, the default is green.

How to Call the Progress Display

Calling the progress display is pretty straight forward. For the above sample .gif the function was called using:

percent_complete(step, total_steps, title="Convert Markdown")

The total_steps was about 2,500 for len(rows) in Stack Exchange Data Dump in CSV format. The step was the current row number as each Stack Exchange Markdown Q&A was converted to Kramdown (for GitHub Pages).

Python Code

The code is straight forward, but a bit longer than the other answers:

def percent_complete(step, total_steps, bar_width=60, title="", print_perc=True):
    import sys

    # UTF-8 left blocks: 1, 1/8, 1/4, 3/8, 1/2, 5/8, 3/4, 7/8
    utf_8s = ["?", "?", "?", "?", "?", "?", "?", "?"]
    perc = 100 * float(step) / float(total_steps)
    max_ticks = bar_width * 8
    num_ticks = int(round(perc / 100 * max_ticks))
    full_ticks = num_ticks / 8      # Number of full blocks
    part_ticks = num_ticks % 8      # Size of partial block (array index)
    
    disp = bar = ""                 # Blank out variables
    bar += utf_8s[0] * full_ticks   # Add full blocks into Progress Bar
    
    # If part_ticks is zero, then no partial block, else append part char
    if part_ticks > 0:
        bar += utf_8s[part_ticks]
    
    # Pad Progress Bar with fill character
    bar += "?" * int((max_ticks/8 - float(num_ticks)/8.0))
    
    if len(title) > 0:
        disp = title + ": "         # Optional title to progress display
    
    # Print progress bar in green: https://stackoverflow.com/a/21786287/6929343
    disp += "\x1b[0;32m"            # Color Green
    disp += bar                     # Progress bar to progress display
    disp += "\x1b[0m"               # Color Reset
    if print_perc:
        # If requested, append percentage complete to progress display
        if perc > 100.0:
            perc = 100.0            # Fix "100.04 %" rounding error
        disp += " {:6.2f}".format(perc) + " %"
    
    # Output to terminal repetitively over the same line using '\r'.
    sys.stdout.write("\r" + disp)
    sys.stdout.flush()

Python Code Notes

A few points:

  • The [ .... ] bracket placeholders requirement in the question are not necessary because there is the fill characters that serve the same purpose. This saves two extra characters to make the progress bar wider.
  • The bar_width keyword parameter can be used depending on screen width. The default of 60 seems a good fit for most purposes.
  • The print_perc=True keyword parameter default can be overridden by passing print_perc=False when calling the function. This would allow a longer progress bar.
  • The title="" keyword parameter defaults to no title. Should you desire one use title="My Title" and : will automatically be added to it.
  • When your program finishes remember to call sys.stdout.write("\r") followed by sys.stdout.flush() to clear the progress display line.

Summary

This answer is a bit longer than the others but it’s important to note it’s a full solution, not part of a solution that you need to add more code to.

Another point is this solution has no dependencies and nothing extra to install. The UTF-8 character set is supported by Python and gnome-terminal was no extra setup required. If you are using Python 2.7 you might require # -*- coding: utf-8 -*- after the shebang. IE as the second line of your program.

The function could be converted to a class with separate init, update, pause (for printing debug stuff to the screen), resume and close methods.

This function was converted from a bash script:

The bash script would display Sony TV volume with libnotify-bin (pop-up bubble message) whenever TV volume was changed. If you are interested in a bash progress bar, please visit the Stack Overflow link.

Edit January 30, 2022

  • Change from 4 ticks to 8 ticks per character.
  • Remove breaks between full blocks.
  • Add color support.

Building on some of the answers here and elsewhere, I’ve written this simple function which displays a progress bar and elapsed/estimated remaining time. Should work on most unix-based machines.

import time
import sys

percent = 50.0
start = time.time()
draw_progress_bar(percent, start)


def draw_progress_bar(percent, start, barLen=20):
sys.stdout.write("\r")
progress = ""
for i in range(barLen):
    if i < int(barLen * percent):
        progress += "="
    else:
        progress += " "

elapsedTime = time.time() - start;
estimatedRemaining = int(elapsedTime * (1.0/percent) - elapsedTime)

if (percent == 1.0):
    sys.stdout.write("[ %s ] %.1f%% Elapsed: %im %02is ETA: Done!\n" % 
        (progress, percent * 100, int(elapsedTime)/60, int(elapsedTime)%60))
    sys.stdout.flush()
    return
else:
    sys.stdout.write("[ %s ] %.1f%% Elapsed: %im %02is ETA: %im%02is " % 
        (progress, percent * 100, int(elapsedTime)/60, int(elapsedTime)%60,
         estimatedRemaining/60, estimatedRemaining%60))
    sys.stdout.flush()
    return

This is quite a simple approach can be used with any loop.

#!/usr/bin/python
for i in range(100001):
    s =  ((i/5000)*'#')+str(i)+(' %')
    print ('\r'+s),

Using @Mark-Rushakoff answer, I worked out a simpler approach, no need to call the sys library. It works with Python 3. Tested in Windows:

from time import sleep
for i in range(21):
    # the exact output you're looking for:
    print ("\r[%-20s] %d%%" % ('='*i, 5*i), end='')
    sleep(0.25)

To be pure python and not make system calls:

from time import sleep

for i in range(21):
    spaces = " " * (20 - i)
    percentage = 5*i
    print(f"\r[{'='*i}{spaces}]{percentage}%", flush=True, end="")
    sleep(0.25)

Try PyProg. PyProg is an open-source library for Python to create super customizable progress indicators & bars.

It is currently at version 1.0.2; it is hosted on Github and available on PyPI (Links down below). It is compatible with Python 3 & 2 and it can also be used with Qt Console.

It is really easy to use. The following code:

import pyprog
from time import sleep

# Create Object
prog = pyprog.ProgressBar(" ", " ", total=34, bar_length=26, complete_symbol="=", not_complete_symbol=" ", wrap_bar_prefix=" [", wrap_bar_suffix="] ", progress_explain="", progress_loc=pyprog.ProgressBar.PROGRESS_LOC_END)
# Update Progress Bar
prog.update()

for i in range(34):
    # Do something
    sleep(0.1)
    # Set current status
    prog.set_stat(i + 1)
    # Update Progress Bar again
    prog.update()

# Make the Progress Bar final
prog.end()

will produce exactly what you want (even the bar length!):

[===========               ] 45%
[===============           ] 60%
[==========================] 100%

For more options to customize the progress bar, go to the Github page of this website.

I actually made PyProg because I needed a simple but super customizable progress bar library. You can easily install it with: pip install pyprog.

PyProg Github: https://github.com/Bill13579/pyprog
PyPI: https://pypi.python.org/pypi/pyprog/

Here is something I have made using the solution by @Mark-Rushakoff. To adaptively adjust to the terminal width.

from time import sleep
import os
import sys
from math import ceil

l = list(map(int,os.popen('stty size','r').read().split()))
col = l[1]
col = col - 6

for i in range(col):
    sys.stdout.write('\r')
    getStr = "[%s " % ('='*i)
    sys.stdout.write(getStr.ljust(col)+"]"+"%d%%" % (ceil((100/col)*i)))
    sys.stdout.flush()
    sleep(0.25)
print("")

Per Steven C. Howell’s comment on Mark Rushakoff’s answer

j = (i + 1) / n
stdout.write('\r')
stdout.write('[%-20s] %d%%' % ('='*int(20*j), 100*j))
stdout.flush()

where i is the current item and n is the total number of items

For Python 3.6 the following works for me to update the output inline:

for current_epoch in range(10):
    for current_step) in range(100):
        print("Train epoch %s: Step %s" % (current_epoch, current_step), end="\r")
print()

import progressbar
import time

# Function to create  
def animated_marker():
    widgets = ['Loading: ', progressbar.Bar('=', '[', ']', '-'), progressbar.Percentage()]
    bar = progressbar.ProgressBar(max_value=200,widgets=widgets).start() 
      
    for i in range(200): 
        time.sleep(0.1)
        bar.update(i+1)
    bar.finish()

# Driver's code 
animated_marker()


The answers/resolutions are collected from stackoverflow, are licensed under cc by-sa 2.5 , cc by-sa 3.0 and cc by-sa 4.0 .

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