import tkinter as tk

 from tkinter import filedialog

 root = tk.Tk()

 root.withdraw()

 file_path = filedialog.askopenfilename()

 import Tkinter, tkFileDialog

 root = Tkinter.Tk()

 root.withdraw()

 file_path = tkFileDialog.askopenfilename()

 import tkinter as tk

 from tkinter import filedialog

 root = tk.Tk()

 root.withdraw()

 file_path = filedialog.askopenfilenames()

 for f in file_path:

     fo = f.split('.')[0]+'.csv'

     with open(fo,'w') as foo:

         with open(f,'r') as fn:

             fn.readline()

             for line in fn.readlines():

                 li = line.strip().split()

                 foo.write('%f,%f\n'%(float(li[1]),float(li[0])))

                 print(li)