删除没有购物行为的人

#!/usr/bin/env python
rd = open('whoBuyWhat.csv')
data3 = open('data_16_16_3.csv')
wr3 = open('delNoBuyed4.5.1.csv','w+')
rdt = rd.readlines()
rdt_id = []
for key in rdt:
  te = key.split(',')
  rdt_id.append(te[0])
i = 1
for key in data3:
  ln = key.split(',')
  if ln[0] in rdt_id:
    wr3.write(key)
  if i == 1:
    print key+'3'
  i = (i+1)%100

rd.close()
data3.close()
wr3.close()