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\n，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：

Python

#!/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)

第二种思路是用转义符\b
转义符\b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：

Python

#!/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)

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：

Python

#!/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

Python

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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')

再发一个类：

Python

#!/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节也提供了一个不错的进度条类，代码如下：

Python

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)

运行结果如下图所示：

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