python源碼:命令列下的進度條顯示

I was finding that I needed a progress indicator for Linux and Windows console applications that could be used to show the user that work was progressing and how much of the total work that had been completed. I finally broke down and wrote this class that seems to do exactly what I wanted. Since I continue to see questions about how to write such a class on Comp.Lang.Python, I thought I'd donate it to this Cookbook archive. 

# CLASS NAME: DLLInterface
#
# Author: Larry Bates (lbates@syscononline.com)
#
# Written: 12/09/2002
#
# Released under: GNU GENERAL PUBLIC LICENSE
#
#
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 -------------------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 ')
        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)

    pb=progressbarClass(100)
    pb.progress(20)
    sleep(0.2)
    pb.progress(47)
    sleep(0.2)
    pb.progress(90)
    sleep(0.2)
    pb.progress(100)
    print "testing 1:"
    pb=progressbarClass(1)
    pb.progress(1)

輸出結果:

 ------------------ % Progress -------------------1
    1    2    3    4    5    6    7    8    9    0
----0----0----0----0----0----0----0----0----0----0
**************************************************

------------------ % Progress -------------------1
    1    2    3    4    5    6    7    8    9    0
----0----0----0----0----0----0----0----0----0----0
ﾲﾲﾲﾲﾲﾲﾲﾲﾲﾲﾲﾲﾲﾲﾲﾲﾲﾲﾲﾲﾲﾲﾲﾲﾲﾲﾲﾲﾲﾲﾲﾲﾲﾲﾲﾲﾲﾲﾲﾲﾲﾲﾲﾲﾲﾲﾲﾲﾲﾲ
testing 1:

------------------ % Progress -------------------1
    1    2    3    4    5    6    7    8    9    0
----0----0----0----0----0----0----0----0----0----0
ﾲﾲﾲﾲﾲﾲﾲﾲﾲﾲﾲﾲﾲﾲﾲﾲﾲﾲﾲﾲﾲﾲﾲﾲﾲﾲﾲﾲﾲﾲﾲﾲﾲﾲﾲﾲﾲﾲﾲﾲﾲﾲﾲﾲﾲﾲﾲﾲﾲﾲ