Python batch modification of the file name of the way to detail

# Batch modification of file names
# Batch change image file names
import os
import re
import sys


path = 'F:\Temp\ZZ'
fileList = (path)		            # Folders to be modified
print("Before modification:"+str(fileList))		    # Files contained in the output folder

currentpath = ()		            # Get the current working directory of the process
(path)		                        # Change the current working directory to the location of the folder to be modified
n = 1		                                # Name variables
for fileName in fileList:		            # Iterate over all files in a folder
    pat=".+\.(jpg|png|jpeg)"		        # Match filename regular expression
    pattern = (pat,fileName)		# Make a match
    (fileName,(str(n)+'.'+pattern[0]))		# File renaming
    n += 1		                        	# Change the number and continue to the next item

(currentpath)		                # Change back to the working directory before the program was run
()		                    # Refresh
print("Modified:"+str((path)))		# Output the files contained in the modified folder

import os

path = 'F:\Temp\ZZ'
# Get all the files in the directory and put them in a list
fileList = (path)

n = 0
for i in fileList:
    # Set old filename (that's path + filename)
    oldname = path +  + fileList[n]  # Add system separator
    # Set new file name
    newname = path +  + 'a' + str(n+1) + '.jpg'
    (oldname, newname)  # Rename a file using the rename method in the os module.
    print(oldname, '======>', newname)
    n += 1

import os

# Output all folder names and file names
path = 'F:\Temp\ZZ'
dataFileList = (path)
for i in dataFileList:
    print(i)


# Read a specific filename
txtFile = []
for filename in dataFileList:
    j = ('.')
    if len(j)==2:
        if j[1]=='txt':
            (filename)