xlswriter 打开文件的时候会清空原有的内容，所以不能用来在原有excel上修改。还好，有openpyxl 这个库，可以完成编辑现有的excel这个功能～
from openpyxl import load_workbook
#Open an xlsx for reading
wb = load_workbook(filename = dest)
#Get the current Active Sheet
ws = wb.get_active_sheet()
#You can also select a particular sheet
#based on sheet name
#ws = wb.get_sheet_by_name("Sheet1")
#Open the csv file
with open(src) as fin:
#read the csv
reader = csv.reader(fin)
#enumerate the rows, so that you can
#get the row index for the xlsx
for index,row in enumerate(reader):
#Assuming space separated,
#Split the row to cells (column)
row = row[0].split()
#Access the particular cell and assign
#the value from the csv row
ws.cell(row=index,column=7).value = row[2]
ws.cell(row=index,column=8).value = row[3]
#save the csb file
wb.save(dest)
