Python中如何写控制台进度条的整理

本文实例讲述了Python显示进度条的方法，是Python程序设计中非常实用的技巧。分享给大家供大家参考。具体方法如下：

首先，进度条和一般的print区别在哪里呢？

答案就是print会输出一个 ，也就是换行符，这样光标移动到了下一行行首，接着输出，之前已经通过stdout输出的东西依旧保留，而且保证我们在下面看到最新的输出结果。

进度条不然，我们必须再原地输出才能保证他是一个进度条，否则换行了怎么还叫进度条？

最简单的办法就是，再输出完毕后，把光标移动到行首，继续在那里输出更长的进度条即可实现，新的更长的进度条把旧的短覆盖，就形成了动画效果。

可以想到那个转义符了吧，那就是 r。

转义符r就可以把光标移动到行首而不换行，转义符n就把光标移动到行首并且换行。

在python中，输出stdout(标准输出)可以使用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+'->'+" ")         sys.stdout.flush()         time.sleep(0.5) print

第二种思路是用转义符
转义符是退格键，也就是说把输出的光标往回退格子，这样就可以不用+=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('#'+'->'+"")         sys.stdout.flush()         time.sleep(0.5) print

光标回退2格，写个#再回退，再写，达到增长的目的了

不过写这么多似乎是废话，在耳边常常听到一句话：那就是不要重复造轮子。实际上python有丰富发lib帮你实现这个东西，你完全可以把心思放在逻辑开发上而不用注意这些小细节的百度云网盘搜索

下面要介绍的就是这个类“progressbar”(http://code.google.com/p/python-progressbar/)，使用easy_install可以方便的安装这个类库，其实就一个文件，拿过来放到文件同一个目录下面也直接可以import过来

如下图所示：

下面就是基本使用举例：

 

 

 

 

 

 

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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()   #高级用法 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 ' % name)             fn()             sys.stdout.write(' ')         except KeyboardInterrupt:             sys.stdout.write(' Skipping example. ')       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(' Quitting examples. ')

再发一个类：

 

 

 

 

 

 

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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(' ------------------- % Progress ------------------- ')         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(" ")         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节也提供了一个不错的进度条类，代码如下：

 

 

 

 

 

 

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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(' ------------------ % Progress -------------------1 ')         self.f.write('  1  2  3  4  5  6  7  8  9  0 ')         self.f.write('----0----0----0----0----0----0----0----0----0----0 ')       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(" ")   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)

运行结果如下图所示：