爬虫学习5.1.2数据存储（无数据库）存储为CSV

1.写CSV文件

import csv
headers=['ID','Username','Password','Age','Country']
rows=[(1001,"qiye","qiye_pass","24","China"),
(1002, "Marry", "Marry_pass", "21", "USA"),
(1003, "Jack", "Jack_pass", "20", "USA"),]

with open('qiye.csv','w') as f:
f_csv= csv.writer(f)
f_csv.writerow(headers)
f_csv.writerows(rows)

2.字典数据
#row列表里的数据 可以是字典数据
import csv
headers=['ID','Username','Password','Age','Country']
rows=[{'ID':1001,'Username':"qiye",'Password':"qiye_pass",'Age':"24",'Country':"China"},
{'ID':1002,'Username':"Marry",'Password':"Marry_pass",'Age':"21",'Country':"USA"},
{'ID':1003,'Username':"Jack",'Password':"Jack_pass",'Age':"20",'Country':"USA"},]

with open('qiye2.csv','w') as f:
f_csv= csv.DictWriter(f,headers)
f_csv.writeheader()
f_csv.writerows(rows)


3.读取数据（列表读取）
import csv
with open('qiye.csv') as f:
f_csv = csv.reader(f)
headers = next(f_csv)
print headers
for row in f_csv:
print row

4.读取数据（索引读取）
python的namedtuple详解：http://blog.csdn.net/kongxx/article/details/51553362

命名分组 然后填入数据，提取数据
import csv
from collections import namedtuple
with open('qiye2.csv') as f:
f_csv = csv.reader(f)
headings = next(f_csv)#迭代获取对象元素
Row = namedtuple('Row',headings)#定义namedtuple类型
for r in f_csv:
row = Row(*r)#获取每行数据创建一个对象
print row.Username,row.Password
print row5.读取到一个字典序列中
import csv
with open('qiye.csv') as f:
f_csv=csv.DictReader(f)
for row in f_csv:
print row.get('Username'),row.get('Password')

6.使用lxml解析 http://seputu.com首页标题 章节和链接等数据
#coding:utf-8
from lxml import etree
import requests
import re
import csv
user_agent = 'Monzilia/4.0 (compatible; MISE 5.5;Windows NT) '
headers = {'User_Agent': user_agent}
r = requests.get('http://seputu.com', headers=headers)
#使用lxml解析网页

html = etree.HTML(r.text)
div_mulus = html.xpath('.//*[@class="mulu"]')
#先找到所有的div class=mulu标记
pattern = re.compile(r'\s*\[(.*)\]\s+(.*)')
rows=[]

for div_mulu in div_mulus:
#找到所有div_h2标记
div_h2 = div_mulu.xpath('./div[@class="mulu-title"]/center/h2/text()')
if len(div_h2) > 0:
h2_title = div_h2[0].encode('utf-8')
a_s = div_mulu.xpath('./div[@class="box"]/ul/li/a')
for a in a_s:
#找到href属性
href = a.xpath('./@href')[0].encode('utf-8')
#找到title属性
box_title = a.xpath('./@title')[0]
pattern = re.compile(r'\s*\[(.*)\]\s+(.*)')
match = pattern.search(box_title)
if match!=None:
date = match.group(1).encode('utf-8')
real_title=match.group(2).encode('utf-8')
#print real_title
content = (h2_title,real_title,href,date)
print content
rows.append(content)
headers = ['title','real_title','href','date']
with open('qiye.csv','w') as f:
f_csv = csv.writer(f,)
f_csv.writerow(headers)
f_csv.writerows(rows)
print 'success!'