python分割文件的常用方法

本文大家整理了一些比较好用的关于python分割文件的方法，方法非常的简单实用。分享给大家供大家参考。具体如下：

例子1 指定分割文件大小

配置文件 config.ini：

代码如下:

[global]
#原文件存放目录
dir1=F:\work\python\3595\pyserver\test
#新文件存放目录
dir2=F:\work\python\3595\pyserver\test1

python 代码如下：

代码如下:

#!/usr/bin/python
# -*- coding: utf-8 -*-
import os,sys,ConfigParser
class file_openate(object):
def __init__(self):
    #初如化读取数据库配置
    dir_config = ConfigParser.ConfigParser()
    file_config=open('config.ini',"rb")
    dir_config.readfp(file_config)
    self.dir1=str(dir_config.get("global","dir1"))
    self.dir1=unicode(self.dir1,'utf8')
    self.dir2=str(dir_config.get("global","dir2"))
    self.dir2=unicode(self.dir2,'utf8')
    file_config.close()
#print self.dir2
#self.dir1="F:\\work\\python\\3595\\pyserver\\test"
def file_list(self):
    input_name_han="软件有不确认性,前期使用最好先备份,以免发生数据丢失,确认备份后,请输入要分割的字节大小,按b来计算".decode('utf-8')
    print input_name_han
    while 1:
input_name=raw_input("number:")
if input_name.isdigit():
    input_name=int(input_name)
    os.chdir(self.dir1)
    for filename in os.listdir(self.dir1):
os.chdir(self.dir1)
#print filename
name, ext = os.path.splitext(filename)
file_size=int(os.path.getsize(filename))
f=open(filename,'r')
chu_nmuber=0
while file_size >= 1:
    #print file_size
    chu_nmuber=chu_nmuber + 1
    if file_size >= input_name:
file_size=file_size - input_name
a=f.read(input_name)
os.chdir(self.dir2)
filename1=name + '-' + str(chu_nmuber) + ext
new_f=open(filename1,'a')
new_f.write(a)
new_f.close()
#print file_size
    else:
a=f.read()
os.chdir(self.dir2)
filename1=name + '-' + str(chu_nmuber) + ext
new_f=open(filename1,'a')
new_f.write(a)
new_f.close()
break
print "分割成功".decode('utf-8') + filename
f.close()
else:
    print "请输入正确的数字,请重新输入".decode('utf-8')
file_name=file_openate()
file_name.file_list()

例子2，按行分割文件大小

代码如下:

#!/usr/bin/env python
#--*-- coding:utf-8 --*--
import os
class SplitFiles():
    """按行分割文件"""
    def __init__(self, file_name, line_count=200):
        """初始化要分割的源文件名和分割后的文件行数"""
        self.file_name = file_name
        self.line_count = line_count
    def split_file(self):
        if self.file_name and os.path.exists(self.file_name):
            try:
                with open(self.file_name) as f : # 使用with读文件
                    temp_count = 0
                    temp_content = []
                    part_num = 1
                    for line in f:
                        if temp_count < self.line_count:
                            temp_count += 1
                        else :
                            self.write_file(part_num, temp_content)
                            part_num += 1
                            temp_count = 1
                            temp_content = []
                        temp_content.append(line)
                    else : # 正常结束循环后将剩余的内容写入新文件中
                        self.write_file(part_num, temp_content)
            except IOError as err:
                print(err)
        else:
            print("%s is not a validate file" % self.file_name)
    def get_part_file_name(self, part_num):
        """"获取分割后的文件名称：在源文件相同目录下建立临时文件夹temp_part_file，然后将分割后的文件放到该路径下"""
        temp_path = os.path.dirname(self.file_name) # 获取文件的路径（不含文件名）
        part_file_name = temp_path + "temp_part_file"
        if not os.path.exists(temp_path) : # 如果临时目录不存在则创建
            os.makedirs(temp_path)
        part_file_name += os.sep + "temp_file_" + str(part_num) + ".part"
        return part_file_name
    def write_file(self, part_num, *line_content):
        """将按行分割后的内容写入相应的分割文件中"""
        part_file_name = self.get_part_file_name(part_num)
        print(line_content)
        try :
            with open(part_file_name, "w") as part_file:
                part_file.writelines(line_content[0])
        except IOError as err:
            print(err)
if __name__ == "__main__":
    sf = SplitFiles(r"F:\multiple_thread_read_file.txt")
    sf.split_file()

上面只是进行了分割了，如果我们又要合并怎么办呢？下面这个例子可以实现分割与合并哦，大家一起看看。

例子3， 分割文件与合并函数

代码如下:

#!/usr/bin/python
##########################################################################
# split a file into a set of parts; join.py puts them back together;
# this is 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 be imported and reused in other applications;
##########################################################################
     
import sys, os
kilobytes = 1024
megabytes = kilobytes * 1000
chunksize = int(1.4 * megabytes)   # default: roughly a floppy
     
def split(fromfile, todir, chunksize=chunksize):
    if not os.path.exists(todir):  # caller handles errors
os.mkdir(todir)    # make dir, read/write parts
    else:
for fname in os.listdir(todir):    # delete any existing files
    os.remove(os.path.join(todir, fname))
    partnum = 0
    input = open(fromfile, 'rb')   # use binary mode on Windows
    while 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.close()    # or simply open().write()
    input.close()
    assert partnum <= 9999 # join sort fails if 5 digits
    return partnum
    
if __name__ == '__main__':
    if len(sys.argv) == 2 and sys.argv[1] == '-help':
print 'Use: split.py [file-to-split target-dir [chunksize]]'
    else:
if len(sys.argv) < 3:
    interactive = 1
    fromfile = raw_input('File to be split? ')       # input if clicked
    todir    = raw_input('Directory to store part files? ')
else:
    interactive = 0
    fromfile, todir = sys.argv[1:3]  # args in cmdline
    if len(sys.argv) == 4: chunksize = int(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 are in', absto
if interactive: raw_input('Press Enter key') # pause if clicked

join_file.py

代码如下:

#!/usr/bin/python
##########################################################################
# join all part files in a dir created by split.py, to recreate file. 
# This is roughly like a 'cat fromdir/* > tofile' command on unix, but is
# more portable and configurable, and exports the join operation as a
# reusable function.  Relies on sort order of file names: must be same
# length.  Could extend split/join to popup Tkinter file selectors.
##########################################################################
     
import os, sys
readsize = 1024
     
def join(fromdir, tofile):
    output = open(tofile, 'wb')
    parts  = os.listdir(fromdir)
    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 be recreated? ')
else:
    interactive = 0
    fromdir, tofile = sys.argv[1:]
absfrom, absto = map(os.path.abspath, [fromdir, tofile])
print '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

希望本文所述对大家的Python程序设计有所帮助。