python pandas合并Sheet,处理列乱序和出现Unnamed列的解决

# -*- coding: UTF-8 -*- 
import xlrd
import pandas as pd
from pandas import DataFrame
from openpyxl import load_workbook

#表格位置
excel_name = '1.xlsx'
# 获取workbook中所有的表格
wb = xlrd.open_workbook(excel_name)
#获取sheets
sheets = wb.sheet_names()

# 循环所需sheet
newdata = DataFrame()
#in后（）里填写需要合并的sheet页数
for i in (3,4,5):
  df = pd.read_excel(excel_name, sheet_name=(i-1), header = None,index_col=0,encoding='utf-8')
  newdata = newdata.append(df,ignore_index = False)
#保存为新的sheet,首先新建sheet,合并后的数据保存到新sheet中
writer = pd.ExcelWriter('1.xlsx',engin='openpyxl')
book = load_workbook(writer.path)
writer.book = book
#利用dataframe.to_excel保存合并后的数据到新的sheet,生成新的sheet命名为newdata
newdata.to_excel(excel_writer=writer,sheet_name="newdata")
writer.save()
writer.close()
print('处理完成！')

df = pd.read_excel(excel_name, sheet_name=(i-1), header = None,index_col=0,encoding='utf-8')