python将某一目录下的多个文件合并为一个文件

import os
import shutil


#get names of files in the directory
def get_filename(filepath,filetype):
    import os
    filename = []
    for root,dirs,files in os.walk(filepath):
        for i in files:
            if filetype in i:
                filename.append(i)
    return filename


def main():
    srcfilepath1 = r'/home/jkx/Anaconda_workspace/task_2017_6_6/BLAST_experiment/bacteria_5000bp_subsequence/'
    filetype = '.txt'
    filename1 = get_filename(srcfilepath1,filetype)
    filename1.sort(key = lambda x:int(x.split('_')[-1].split('.')[0]))
    outfilename = 'BacteriaVirus_5000bp_subsequence_mark_' + str(i + 1) + '.txt'
    outfile = open(outfilename,'a')
    for i in range(len(filename1)):
        infilename1 = srcfilepath1 + filename1[i]
        infile1 = open(infilename1,'r')
        shutil.copyfileobj(infile1,outfile)
        infile1.close()
    outfile.close()    
    
    
main()    

合并时主要用到python的shutil模块的copyfileobj方法，关于该方法的介绍详见官方文档：

https://docs.python.org/2/library/shutil.html