Python 3.4向cs写入列表

Question

我无法将列表写入csv。我当前的代码将列表（由字符串组成）写入每个字符之间有空格的文件。这是我正在处理的问题，最有可能出现在最后3或4行：

import csv
import sys
import collections

c1 = set()
c2 = set()
c3 = set()

new=(r'file')
old=(r'file2')

with open(new, 'r') as newfile:
    newreader = csv.reader(newfile, delimiter=(','))
    for row in newreader:
        c1.add(row[0])

with open(old, 'r') as oldfile:
    oldreader = csv.reader(oldfile, delimiter=(','))
    for row in oldreader:
        c2.add(row[0])

c3=c2-c1
c1=c2|c3
print(c1)
print(c2)
print(c3)

with open (r'csv1.csv', 'w', newline='') as write_file:
    write=csv.writer(write_file, delimiter=' ')

    write.writerows(list(c1))

提前谢谢你的帮助。