Python中如何寫控制檯進度條的整理

本文實例講述了Python顯示進度條的方法，是Python程序設計中很是實用的技巧。分享給你們供你們參考。具體方法以下：

首先，進度條和通常的print區別在哪裏呢？

答案就是print會輸出一個\n，也就是換行符，這樣光標移動到了下一行行首，接着輸出，以前已經經過stdout輸出的東西依舊保留，並且保證咱們在下面看到最新的輸出結果。

進度條否則，咱們必須再原地輸出才能保證他是一個進度條，不然換行了怎麼還叫進度條？

最簡單的辦法就是，再輸出完畢後，把光標移動到行首，繼續在那裏輸出更長的進度條便可實現，新的更長的進度條把舊的短覆蓋，就造成了動畫效果。

能夠想到那個轉義符了吧，那就是\ r。

轉義符r就能夠把光標移動到行首而不換行，轉義符n就把光標移動到行首而且換行。

在python中，輸出stdout(標準輸出)可使用sys.stdout.write
例如：

 

 

 

 

 

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#!/usr/bin/env python # -*- coding=utf-8 -*- #Using GPL v2 #Author: ihipop@gmail.com ##2010-10-27 22:07 """ Usage: Just A Template """ from __future__ import division   import sys,time j = '#' if __name__ == '__main__':     for i in range(1,61):         j += '#'         sys.stdout.write(str(int((i/60)*100))+'%  ||'+j+'->'+"\r")         sys.stdout.flush()         time.sleep(0.5) print

第二種思路是用轉義符\b
轉義符\b是退格鍵，也就是說把輸出的光標往回退格子，這樣就能夠不用+=了，例如：

 

 

 

 

 

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#!/usr/bin/env python # -*- coding=utf-8 -*- #Using GPL v2 #Author: ihipop@gmail.com #2010-10-27 22:07 """ Usage: Just A Template """ from __future__ import division   import sys,time if __name__ == '__main__':     for i in range(1,61):         sys.stdout.write('#'+'->'+"\b\b")         sys.stdout.flush()         time.sleep(0.5) print

光標回退2格，寫個#再回退，再寫，達到增加的目的了

不過寫這麼多彷佛是廢話，在耳邊經常聽到一句話：那就是不要重複造輪子。實際上python有豐富發lib幫你實現這個東西，你徹底能夠把心思放在邏輯開發上而不用注意這些小細節的百度雲網盤搜索

下面要介紹的就是這個類「progressbar」(http://code.google.com/p/python-progressbar/)，使用easy_install能夠方便的安裝這個類庫，其實就一個文件，拿過來放到文件同一個目錄下面也直接能夠import過來

以下圖所示：

下面就是基本使用舉例：

 

 

 

 

 

 

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#!/usr/bin/env python # -*- coding=utf-8 -*- #Using GPL v2 #Author: ihipop@gmail.com #2010-10-27 22:53 """ Usage: Just A Template """ from __future__ import division   import sys,time from progressbar import * total = 1000   #基本用法 progress = ProgressBar() for i in progress(range(total)):   time.sleep(0.01)   pbar = ProgressBar().start() for i in range(1,1000):     pbar.update(int((i/(total-1))*100))     time.sleep(0.01) pbar.finish()   #高級用法 widgets = ['Progress: ', Percentage(), ' ', Bar(marker=RotatingMarker('>-=')),            ' ', ETA(), ' ', FileTransferSpeed()] pbar = ProgressBar(widgets=widgets, maxval=10000000).start() for i in range(1000000):   # do something   pbar.update(10*i+1)   time.sleep(0.0001) pbar.finish()

官方示例:http://code.google.com/p/python-progressbar/source/browse/progressbar/examples.py

 

 

 

 

 

 

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# coding:utf-8 import sys import time from progressbar import AnimatedMarker, Bar, BouncingBar, Counter, ETA, \     FileTransferSpeed, FormatLabel, Percentage, \     ProgressBar, ReverseBar, RotatingMarker, \     SimpleProgress, Timer   examples = []   def example(fn):     try:         name = 'Example %d' % int(fn.__name__[7:])     except:         name = fn.__name__       def wrapped():         try:             sys.stdout.write('Running: %s\n' % name)             fn()             sys.stdout.write('\n')         except KeyboardInterrupt:             sys.stdout.write('\nSkipping example.\n\n')       examples.append(wrapped)     return wrapped   @example def example0():     pbar = ProgressBar(widgets=[Percentage(), Bar()], maxval=300).start()     for i in range(300):         time.sleep(0.01)         pbar.update(i + 1)     pbar.finish()   @example def example1():     widgets = ['Test: ', Percentage(), ' ', Bar(marker=RotatingMarker()),                ' ', ETA(), ' ', FileTransferSpeed()]     pbar = ProgressBar(widgets=widgets, maxval=10000000).start()     for i in range(1000000):         # do something         pbar.update(10 * i + 1)     pbar.finish()   @example def example2():     class CrazyFileTransferSpeed(FileTransferSpeed):         """It's bigger between 45 and 80 percent."""           def update(self, pbar):             if 45 < pbar.percentage() < 80:                 return 'Bigger Now ' + FileTransferSpeed.update(self, pbar)             else:                 return FileTransferSpeed.update(self, pbar)       widgets = [CrazyFileTransferSpeed(), ' <<<', Bar(), '>>> ',                Percentage(), ' ', ETA()]     pbar = ProgressBar(widgets=widgets, maxval=10000000)     # maybe do something     pbar.start()     for i in range(2000000):         # do something         pbar.update(5 * i + 1)     pbar.finish()   @example def example3():     widgets = [Bar('>'), ' ', ETA(), ' ', ReverseBar('<')]     pbar = ProgressBar(widgets=widgets, maxval=10000000).start()     for i in range(1000000):         # do something         pbar.update(10 * i + 1)     pbar.finish()   @example def example4():     widgets = ['Test: ', Percentage(), ' ',                Bar(marker='0', left='[', right=']'),                ' ', ETA(), ' ', FileTransferSpeed()]     pbar = ProgressBar(widgets=widgets, maxval=500)     pbar.start()     for i in range(100, 500 + 1, 50):         time.sleep(0.2)         pbar.update(i)     pbar.finish()   @example def example5():     pbar = ProgressBar(widgets=[SimpleProgress()], maxval=17).start()     for i in range(17):         time.sleep(0.2)         pbar.update(i + 1)     pbar.finish()   @example def example6():     pbar = ProgressBar().start()     for i in range(100):         time.sleep(0.01)         pbar.update(i + 1)     pbar.finish()   @example def example7():     pbar = ProgressBar()  # Progressbar can guess maxval automatically.     for i in pbar(range(80)):         time.sleep(0.01)   @example def example8():     pbar = ProgressBar(maxval=80)  # Progressbar can't guess maxval.     for i in pbar((i for i in range(80))):         time.sleep(0.01)   @example def example9():     pbar = ProgressBar(widgets=['Working: ', AnimatedMarker()])     for i in pbar((i for i in range(50))):         time.sleep(.08)   @example def example10():     widgets = ['Processed: ', Counter(), ' lines (', Timer(), ')']     pbar = ProgressBar(widgets=widgets)     for i in pbar((i for i in range(150))):         time.sleep(0.1)   @example def example11():     widgets = [FormatLabel('Processed: %(value)d lines (in: %(elapsed)s)')]     pbar = ProgressBar(widgets=widgets)     for i in pbar((i for i in range(150))):         time.sleep(0.1)   @example def example12():     widgets = ['Balloon: ', AnimatedMarker(markers='.oO<a href="http://www.jobbole.com/members/weiboyes8848">@*</a> ')]     pbar = ProgressBar(widgets=widgets)     for i in pbar((i for i in range(24))):         time.sleep(0.3)   @example def example13():     # You may need python 3.x to see this correctly     try:         widgets = ['Arrows: ', AnimatedMarker(markers='←↖↑↗→↘↓↙')]         pbar = ProgressBar(widgets=widgets)         for i in pbar((i for i in range(24))):             time.sleep(0.3)     except UnicodeError:         sys.stdout.write('Unicode error: skipping example')   @example def example14():     # You may need python 3.x to see this correctly     try:         widgets = ['Arrows: ', AnimatedMarker(markers='◢◣◤◥')]         pbar = ProgressBar(widgets=widgets)         for i in pbar((i for i in range(24))):             time.sleep(0.3)     except UnicodeError:         sys.stdout.write('Unicode error: skipping example')   @example def example15():     # You may need python 3.x to see this correctly     try:         widgets = ['Wheels: ', AnimatedMarker(markers='◐◓◑◒')]         pbar = ProgressBar(widgets=widgets)         for i in pbar((i for i in range(24))):             time.sleep(0.3)     except UnicodeError:         sys.stdout.write('Unicode error: skipping example')   @example def example16():     widgets = [FormatLabel('Bouncer: value %(value)d - '), BouncingBar()]     pbar = ProgressBar(widgets=widgets)     for i in pbar((i for i in range(180))):         time.sleep(0.05)   @example def example17():     widgets = [FormatLabel('Animated Bouncer: value %(value)d - '),                BouncingBar(marker=RotatingMarker())]       pbar = ProgressBar(widgets=widgets)     for i in pbar((i for i in range(180))):         time.sleep(0.05)   @example def example18():     widgets = [Percentage(),                ' ', Bar(),                ' ', ETA(),                ' ', AdaptiveETA()]     pbar = ProgressBar(widgets=widgets, maxval=500)     pbar.start()     for i in range(500):         time.sleep(0.01 + (i < 100) * 0.01 + (i > 400) * 0.9)         pbar.update(i + 1)     pbar.finish()   @example def example19():     pbar = ProgressBar()     for i in pbar([]):         pass     pbar.finish()   try:     for example in examples:         example() except KeyboardInterrupt:     sys.stdout('\nQuitting examples.\n')

再發一個類：

 

 

 

 

 

 

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#!/usr/bin/env python # -*- coding=utf-8 -*- #Using GPL v2 #Author: ihipop@gmail.com #2010-10-30 13:59 """ Usage: Just A Template """ class progressbarClass:     def __init__(self, finalcount, progresschar=None):         import sys         self.finalcount=finalcount         self.blockcount=0         #         # See if caller passed me a character to use on the         # progress bar (like "*").  If not use the block         # character that makes it look like a real progress         # bar.         #         if not progresschar: self.block=chr(178)         else:                self.block=progresschar         #         # Get pointer to sys.stdout so I can use the write/flush         # methods to display the progress bar.         #         self.f=sys.stdout         #         # If the final count is zero, don't start the progress gauge         #         if not self.finalcount : return         self.f.write('\n------------------- % Progress -------------------\n')         return       def progress(self, count):         #         # Make sure I don't try to go off the end (e.g. >100%)         #         count=min(count, self.finalcount)         #         # If finalcount is zero, I'm done         #         if self.finalcount:             percentcomplete=int(round(100*count/self.finalcount))             if percentcomplete < 1: percentcomplete=1         else:             percentcomplete=100           #print "percentcomplete=",percentcomplete         blockcount=int(percentcomplete/2)         #print "blockcount=",blockcount         if blockcount > self.blockcount:             for i in range(self.blockcount,blockcount):                 self.f.write(self.block)                 self.f.flush()           if percentcomplete == 100: self.f.write("\n")         self.blockcount=blockcount         return   if __name__ == "__main__":     from time import sleep     pb=progressbarClass(8,"*")     count=0     while count<9:         count+=1         pb.progress(count)         sleep(0.2)

另外，python cookbook中11.1節也提供了一個不錯的進度條類，代碼以下：

 

 

 

 

 

 

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import sys   class progressbar(object):       def __init__(self, finalcount, block_char='.'):         self.finalcount = finalcount         self.blockcount = 0         self.block = block_char         self.f = sys.stdout         if not self.finalcount:             return         self.f.write('\n------------------ % Progress -------------------1\n')         self.f.write('  1  2  3  4  5  6  7  8  9  0\n')         self.f.write('----0----0----0----0----0----0----0----0----0----0\n')       def progress(self, count):         count = min(count, self.finalcount)         if self.finalcount:             percentcomplete = int(round(100.0 * count / self.finalcount))             if percentcomplete < 1:                 percentcomplete = 1         else:             percentcomplete = 100         blockcount = int(percentcomplete // 2)         if blockcount <= self.blockcount:             return         for i in range(self.blockcount, blockcount):             self.f.write(self.block)         self.f.flush()         self.blockcount = blockcount         if percentcomplete == 100:             self.f.write("\n")   if __name__ == "__main__":     from time import sleep     pb = progressbar(8, "*")     for count in range(1, 9):         pb.progress(count)         sleep(0.2)     pb = progressbar(100)     pb.progress(20)     sleep(0.3)     pb.progress(47)     sleep(0.3)     pb.progress(90)     sleep(0.3)     pb.progress(100)     print "testing 1:"     pb = progressbar(1)     pb.progress(1)

運行結果以下圖所示：