Python CSV：循环日期到特定列

Question

CSV文件输出：

Date (Column Header)
Week, 5-Dec, 4-Dec, 3-Dec, 2-Dec, 1-Dec 
Week, 5-Dec, 4-Dec, 3-Dec, 2-Dec, 1-Dec

为文件中的每一行输出此值。

当前代码：

import csv

with open("C:\E\cs2.csv", 'r') as input, open('date.csv', 'w') as output:
 reader = csv.reader(input, delimiter = ',')
 writer = csv.writer(output, delimiter = ',',lineterminator='\n')

 all = []
 row = next(reader)
 all.append(row)

for row in reader:        
   for d in ('Week','12-1','12-2','12-3','12-4','12-5'):
     row.insert(5,d)
     all.append(row)
writer.writerows(all)

问题：目前我正在编写每一行的每个日期，从第6列开始。我想在第6列循环上面列出的具体日期，但是以垂直方式。

Desired Output on Column 6:
  Date(Column Header)
  Week
  12-1
  12-2, etc.