求指导编写一个python代码

求指导编写一个python代码，要实现：
        1、一次性遍历指定文件夹内（包括下面的所有子文件夹）的所有txt文件；
        2、将所有txt文件汇总入一个excel表格：表格的第一列为序数；第二列为单个txt文件的文件名，第三列为单个txt文件内字符（不包括空格）的数量。
        刚开始学python，尝试了多次没有成功，希望有人能指导我，请会编程的同学把代码（最好带注释）发给我，感谢！

import os
import glob
s = []
lst = []
for filename in glob.glob(r'D:\SteamLibrary\*.txt'):#举个例子~遍历问目录下所有txt文件
    s.append(filename)#存文件名
    try:
        f = open(filename)
        contents = f.read()
    except NameError:
        f.close()
    else:
        words = contents.rstrip()
        num_words = len(words)
        lst.append(num_words)#存字数
        f.close()

import xlwt
#需要处理excel的库，cmd打开复制pip install xlwt
workbook = xlwt.Workbook(encoding='utf-8')
booksheet = workbook.add_sheet('Sheet 1', cell_overwrite_ok=True)
for i in range(len(s)):#递归把数据写进去
    rowdata = [i+1,s[i],lst[i]]
    for m in range(3):
        booksheet.write(i,m,rowdata[m])
workbook.save('test_xlwt.xls')  

加油，我也刚学，共同努力

dgafqasq 发表于 2019-3-5 22:49
import os
import glob
s = []

C:\Python37-32\python.exe C:/Users/Lenovo/PycharmProjects/content/test.py
Traceback (most recent call last):
  File "C:/Users/Lenovo/PycharmProjects/contenti/test.py", line 9, in <module>
    contents = f.read()
UnicodeDecodeError: 'gbk' codec can't decode byte 0xad in position 12: illegal multibyte sequence

Process finished with exit code 1

dgafqasq 发表于 2019-3-5 22:49
import os
import glob
s = []

C:\Python37-32\python.exe C:/Users/Lenovo/PycharmProjects/content/test.py
Traceback (most recent call last):
  File "C:/Users/Lenovo/PycharmProjects/contenti/test.py", line 9, in <module>
    contents = f.read()
UnicodeDecodeError: 'gbk' codec can't decode byte 0xad in position 12: illegal multibyte sequence

Process finished with exit code 1

dgafqasq 发表于 2019-3-5 22:49
import os
import glob
s = []

报错了，请问如何处理呢

f = open(filename) 改成了 f = open(filename,encoding = 'gbk',errors = 'ignore') 运行出来时成功的，搞定了，谢谢大神