带有标题的控制台中的文本进度栏

Question

I am using this answer to print a progress bar but want it to print what exactly it is doing while it is progressing. I added a parameter called "current_task" to print_progress() and now would like it to perform as follows. How do I do this?

FYI: I'm on on a Unix system: macOS Sierra

print_progress(7,10,...remaining params..., "downloading contacts")

should print this

Currently downloading contacts
Progress |████████████████████████████████---------------------| 70% Complete

the subsequent call of

print_progress(8,10,...remaining params..., "downloading companies")

should cause the progress bar to change in place to now look like this

Currently downloading companies
Progress |████████████████████████████████████-------------| 80% Complete

Answer 1

Here's a modified version of Greenstick's code that supports a header line. It uses an ANSI control sequence '\\x1b[3A' to move the terminal cursor up 3 lines after it's printed the header & progress bar.

This updated version works correctly on Python 2 (tested on 2.6.6) & Python 3 (tested on 3.6.0). It also erases the previous contents of the header line so you don't get stray characters if the current header is shorter than the previous one.

from __future__ import print_function
from time import sleep

# Print iterations progress
#Originally written by Greensticks, modified by PM 2Ring
def printProgressBar (iteration, total, prefix='', suffix='', decimals=1, 
    length=100, fill=u'\u2588', header=''):
    """
    Call in a loop to create terminal progress bar
    @params:
        iteration   - Required  : current iteration (Int)
        total       - Required  : total iterations (Int)
        prefix      - Optional  : prefix string (Str)
        suffix      - Optional  : suffix string (Str)
        decimals    - Optional  : positive number of decimals in percent complete (Int)
        length      - Optional  : character length of bar (Int)
        fill        - Optional  : bar fill character (Str)
        header      - Optional  : header string (Str)
    """
    # Clear the current line and print the header
    print('\x1b[2K', header, '\n')
    percent = ("{0:." + str(decimals) + "f}").format(100 * (iteration / float(total)))
    filledLength = int(length * iteration // total)
    # Generate and print the bar
    bar = fill * filledLength + u'-' * (length - filledLength)
    print('%s |%s| %s%% %s\x1b[3A' % (prefix, bar, percent, suffix))
    # Print New Lines on Complete
    if iteration == total: 
        print('\n' * 2)

# Test

maxi = 10
delay = 0.5

# Initial call to print 0% progress
header = 'Currently downloading contacts now'
printProgressBar(0, maxi, prefix='Progress:', suffix='Complete', length=50, header=header)
for i in range(1, 8):
    # Do stuff...
    sleep(delay)
    # Update Progress Bar
    printProgressBar(i, maxi, prefix='Progress:', suffix='Complete', length=50, header=header)

header = 'Currently downloading companies'
for i in range(8, maxi + 1):
    # Do stuff...
    sleep(delay)
    # Update Progress Bar
    printProgressBar(i, maxi, prefix='Progress:', suffix='Complete', length=50, header=header)

print('Finished')

Note that if you don't supply a header line you'll get a blank header line. Please make sure that the header line will actually fit on one line of your terminal, and definitely don't put any '\\n' chars in it!

---

You could make this progress bar more versatile by using threading , as illustrated in this Scrolling Timer I wrote a few months ago.

---

Here's a version of printProgressBar that disables the cursor so we don't need that extra pace at the start of the cursor.

def printProgressBar (iteration, total, prefix='', suffix='', decimals=1, 
    length=100, fill=u'\u2588', header=''):
    """
    Call in a loop to create terminal progress bar
    @params:
        iteration   - Required  : current iteration (Int)
        total       - Required  : total iterations (Int)
        prefix      - Optional  : prefix string (Str)
        suffix      - Optional  : suffix string (Str)
        decimals    - Optional  : positive number of decimals in percent complete (Int)
        length      - Optional  : character length of bar (Int)
        fill        - Optional  : bar fill character (Str)
        header      - Optional  : header string (Str)
    """
    if iteration == 0:
        # Turn off the cursor
        print("\x1b[?25l", end='')
    # Clear the current line & print the header
    print('\x1b[2K', header, sep= '', end='\n\n')
    percent = ("{0:." + str(decimals) + "f}").format(100 * (iteration / float(total)))
    filledLength = int(length * iteration // total)
    # Generate and print the bar
    bar = fill * filledLength + u'-' * (length - filledLength)
    print('%s |%s| %s%% %s\x1b[3A' % (prefix, bar, percent, suffix))
    # Print New Lines on Complete
    if iteration == total: 
        # Turn on the cursor, and skip a few lines
        print("\x1b[?25h", end='\n\n')

One problem with doing this is that if we terminate the program early (eg by hitting Ctrl C ) while the cursor is disabled, it will still be disabled after the program edits. On Linux, you can just send the ANSI sequence to turn the cursor back on with a simple Bash command:

echo -e "\e[?25h"

although it's easier to reset the terminal:

echo -e "\ec"

Of course, we could also trap signal.SIGINT and add a handler function to turn the cursor on before the program exits, but that adds extra complexity to the code.