python中如何通过循环遍历分离数据

# coding=utf-8
 
# 跳过列表表头的引入依赖
from itertools import islice
 
import csv
 
# 用于储存重复的数据
re_l = []
# 用于储存重复数据之外剩余的数据
n_l = []
 
# 用于储存要对比的所有数据的索引（即name），其中剔除为空的name
values = []
 
# 获取所有数据中name值不为空数据的name
with open('./mRNA.csv', 'r') as f:
    # 跳过列表表头
    values_reader = islice(f, 1, None)
    for value in values_reader:
        if len(value.split(',', 2)[1]) != 0:
            values.append(value.split(',', 2)[1])
 
# 把数据分类
with open('./mRNA.csv', 'r') as f1:
    reader = islice(f1, 1, None)
    for row in reader:
        if not row.split(',', 1)[0] in values:
            n_l.append(row)
        else:
            # 重复的数据
            re_l.append(row)
 
# 把重复的数据写入remRNA.csv
with open('./remRNA.csv', 'w') as f2:
    re_cw = csv.writer(f2)
    for re_item in re_l:
        re_cw.writerow(re_item.split(','))
 
# 把重复的数据写入nmRNA.csv
with open('./nmRNA.csv', 'w') as f3:
    n_cw = csv.writer(f3)
    for n_item in n_l:
        n_cw.writerow(n_item.split(','))