Python：操作文件

python操作文件库不需要安装其他module,文件操作类库是python语言自身支持的操作。

判定文件是否存在：os.path.isfile(filePath)

import os
import sys

if __name__=='__main__':
    filePath='d:\FTP\HUAWEI\1.txt'
    
    if os.path.isfile(filePath):
        #os.remove() will remove a file.
        #os.rmdir() will remove an empty directory.
        #shutil.rmtree() will delete a directory and all its contents.
        os.remove(filePath)
        print 'file has exists,was removed...'
        
    #if the file not exists will be created.
    fileObj=open(filePath,'w')

    # loop the list of dir
    for folder in os.listdir('D:\FTP\HUAWEI\20160513'):
        fileObj.write(folder+',')

    #if forget to close the file oject,the operate is not flush util the current process exit.
    fileObj.close()

    #read file
    fileReadObj=open('d:\FTP\HUAWEI\2.txt','r')
    fileWriterObj=open('d:\FTP\HUAWEI\3.txt','a')
    fileWriterObj.write('---------------------------------------------------------
')
    for line in fileReadObj.readlines():
        fileWriterObj.write('select '+ line+' id union all ')
    fileReadObj.close()
    fileWriterObj.close()

参考资料：

https://docs.python.org/3/library/os.html#os.remove

http://www.pythonforbeginners.com/files/reading-and-writing-files-in-python