如何用Python实现分割合并文件

import sys,os

kilobytes = 1024

megabytes = kilobytes*1000

chunksize = int(200*megabytes)#default chunksize

def split(fromfile,todir,chunksize=chunksize):

    if not os.path.exists(todir):#check whether todir exists or not

        os.mkdir(todir)         

    else:

        for fname in os.listdir(todir):

            os.remove(os.path.join(todir,fname))

    partnum = 0

    inputfile = open(fromfile,'rb')#open the fromfile

    while True:

        chunk = inputfile.read(chunksize)

        if not chunk:             #check the chunk is empty

            break

        partnum += 1

        filename = os.path.join(todir,('part%04d'%partnum))

        fileobj = open(filename,'wb')#make partfile

        fileobj.write(chunk)         #write data into partfile

        fileobj.close()

    return partnum

if __name__=='__main__':

        fromfile  = input('File to be split?')

        todir     = input('Directory to store part files?')

        chunksize = int(input('Chunksize to be split?'))

        absfrom,absto = map(os.path.abspath,[fromfile,todir])

        print('Splitting',absfrom,'to',absto,'by',chunksize)

        try:

            parts = split(fromfile,todir,chunksize)

        except:

            print('Error during split:')

            print(sys.exc_info()[0],sys.exc_info()[1])

        else:

            print('split finished:',parts,'parts are in',absto)

Python 3.4.1 (v3.4.1:c0e311e010fc, May 18 2014, 10:45:13) [MSC v.1600 64 bit (AMD64)] on win32

Type "copyright", "credits" or "license()" for more information.

>>> ================================ RESTART ================================

>>>

File to be split?F:\X-MEN1.rar

Directory to store part files?F:\split

Chunksize to be split?400000000

Splitting F:\X-MEN1.rar to F:\split by 400000000

split finished: 4 parts are in F:\split

>>>

import sys,os

def joinfile(fromdir,filename,todir):

    if not os.path.exists(todir):

        os.mkdir(todir)

    if not os.path.exists(fromdir):

        print('Wrong directory')

    outfile = open(os.path.join(todir,filename),'wb')

    files = os.listdir(fromdir) #list all the part files in the directory

    files.sort()                #sort part files to read in order

    for file in files:

        filepath = os.path.join(fromdir,file)

        infile = open(filepath,'rb')

        data = infile.read()

        outfile.write(data)

        infile.close()

    outfile.close()

if __name__=='__main__':

        fromdir = input('Directory containing part files?')

        filename = input('Name of file to be recreated?')

        todir   = input('Directory to store recreated file?')

        try:

            joinfile(fromdir,filename,todir)

        except:

            print('Error joining files:')

            print(sys.exc_info()[0],sys.exc_info()[1])

Python 3.4.1 (v3.4.1:c0e311e010fc, May 18 2014, 10:45:13) [MSC v.1600 64 bit (AMD64)] on win32

Type "copyright", "credits" or "license()" for more information.

>>> ================================ RESTART ================================

>>>

Directory containing part files?F:\split

Name of file to be recreated?xman1.rar

Directory to store recreated file?F:\

>>>