ppt转换为text

测试用的代码，所以比较乱。
import win32com
from win32com.client import Dispatch, constants
ppt = win32com.client.Dispatch('PowerPoint.Application')
ppt.Visible = 1
pptSel = ppt.Presentations.Open("d:\\1.ppt")
win32com.client.gencache.EnsureDispatch('PowerPoint.Application')
f = file("d:\\1.txt","w")
slide_count = pptSel.Slides.Count
for i in range(1,slide_count + 1):
    shape_count = pptSel.Slides(i).Shapes.Count
    print shape_count
    for j in range(1,shape_count + 1):
        if pptSel.Slides(i).Shapes(j).HasTextFrame:
            s = pptSel.Slides(i).Shapes(j).TextFrame.TextRange.Text
            f.write(s.encode('utf-8') + "\n")        
f.close()
ppt.Quit()