Python implements the method of splitting files and merging files

In this paper, we describe how Python implements split files and merge files. Share to everyone for your reference. Specific as follows:

The split file split.py is as follows:

#!/usr/bin/python########################################################################### split a file into a set of parts; Join.py puts them back together;# this was a customizable version of the standard UNIX split command-line # utility; Because it is written in Python, it also works on Windows and# can be easily modified; Because it exports a function, its logic can # also is imported and reused in other applications;######################### ################################################ #import sys, oskilobytes = 1024megabytes = kilobytes * 1000chunksize = INT (1.4 * megabytes) # default:roughly a floppydef split (FromFile, Todir, chunksize=chunksize): If not os.path.exist S (todir): # Caller handles Errors Os.mkdir (todir) # make dir, read/write parts else:for fname in Os.listdir (t     Odir): # Delete any existing files Os.remove (Os.path.join (Todir, fname)) partnum = 0 input = open (FromFile, ' RB ') # Use binary mode on Windows 1: # eof=empty STRing from read chunk = Input.read (chunksize) # Get Next part <= chunksize if not chunk:break partnum = partnum+1 filename = Os.path.join (Todir, (' part%04d '% partnum)) fileobj = open (filename, ' WB ') fileobj.write (chunk) Fileobj.clo SE () # or simply open (). Write () Input.close () assert Partnum <= 9999 # Join sort fails if 5 digits return p ARTNUMIF __name__ = = ' __main__ ': If Len (sys.argv) = = 2 and sys.argv[1] = = '-help ': print ' Use:split.py [File-to-split ta Rget-dir [chunksize]] ' Else:if len (sys.argv) < 3:interactive = 1 FromFile = raw_input (' File to is split? ') # input if clicked Todir = Raw_input (' Directory to store ' files? ') else:interactive = 0 FromFile, Todir = sys.argv[1:3] # args in CmdLine if Len (sys.argv) = = 4:chunksize = I NT (Sys.argv[3]) 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 ' in ' , Absto if Interactive:raw_input (' Press Enter key ') # pause if clicked

The merged files are join_file.py as follows:

#!/usr/bin/python########################################################################### join all the files in A dir created by split.py, to recreate file.  # This was roughly like a ' cat fromdir/* > ToFile ' command on UNIX, but was # more portable and configurable, and exports The join operation as a # reusable function. Relies on sort order of file names:must is same # length. Could extend Split/join to popup Tkinter file selectors.############################################################# ############ #import os, sysreadsize = 1024def join (fromdir, tofile): output = open (ToFile, ' wb ') parts = Os.listdir (fromdi R) parts.sort () for filename in Parts:filepath = Os.path.join (fromdir, filename) fileobj = open (filepath, ' RB ') while 1:filebytes = Fileobj.read (readsize) if not filebytes:break output.write (filebytes) fileobj.close () Output.close ( if __name__ = = ' __main__ ': If Len (sys.argv) = = 2 and sys.argv[1] = = '-help ': print ' Use:join.py [from-dir-name to-file- Name] 'Else:if len (sys.argv)! = 3:interactive = 1 Fromdir = raw_input (' Directory containing part files? ') ToFile = Raw_input (' Name of file to is recreated? ') else:interactive = 0 Fromdir, ToFile = sys.argv[1:] absfrom, Absto = Map (Os.path.abspath, [Fromdir, ToFile]) pr int ' joining ', Absfrom, ' to make ', Absto try:join (Fromdir, ToFile) except:print ' Error joining files: ' Print sys  . Exc_info () [0], Sys.exc_info () [1] else:print ' Join complete:see ', Absto if Interactive:raw_input (' Press Enter key ') # pause If clicked

Hopefully this article will help you with Python programming.

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