Python中如何写控制台进度条的整理

python基础

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2018-3-5

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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:

  
#!/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:

   
#!/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
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:

    
#!/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

   
# 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:

    
#!/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:

   
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:

希望本文所述对大家Python程序设计的学习有所帮助。
http://blog.ihipop.info/2010/10/1736.html

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