Scrapy爬取Seair Exim Solutions (https://www.seair.co.in/)印度进出口交易信息
在这个网站上捕捉到下列可用信息，便试着爬一爬
爬虫工具
pip install scrapy
我使用scrapy/quotesbot （https://github.com/scrapy/quotesbot.git）作为初始项目环境, 在spideris件夹下编写自己的爬虫文件
代码定义了spider name为'seair'，爬虫程序起始url start_urls，针对爬取网页的response，进行html语法分析。
由于在response中使用XPath、CSS查询十分普遍，因此，Scrapy提供了两个实用的快捷方式: `response.xpath()` 及 `response.css()`。
我使用的是xpath（`https://www.w3schools.com/xml/xpath_intro.asp`）
Selector调试
为方便在response中查询，可在安装`ipython`后运行:
scrapy shell https://www.seair.co.in
爬取目标url， 可以使用：
response.headers
response.body
等命令查看response详情，观测到抓取成功后便可在ipython中进行selector调试，在response中检索所需数据，例如：
response.xpath('...').extract() 等
爬取数据的同时也要搜集下一级url，scrapy针对加入的url会自动去重，所以此处我简单地把所有页面的上的url都加入搜索集中：
reponse.xpath('//a/@href').extract()
运行爬虫
scrapy crawl seair -o data.json
爬虫名称及存储文件名自定义，起初慢得一匹，后来搜到一家公司的产品里竟然有支持加速的docker，教程里一条token贴到docker配置文件里就能work（https://rallets.com/ 登录后在我的账户下有开发者平台），果断试了一下，两小时爬到了117m数据。
数据清洗
爬取到数据后开始清理，scrapy文件写得比较简易，数据格式比较杂乱，但也有数据全面的优势，存在潜在价值。针对捕捉到可用数据，分析数据格式，利用正则表达式进行匹配、分析、重组。
"Argentina Import Sample 1", "IMPORTER NAME ", "PEPSICO DE ARGENTINA SRL,JULIO A ROCA 4735 FLORIDA", " Product Description", " IITRIC ACID.CARBOXYLIC ACIDS WITH ALCOHOL FUNCTION, BUT WITHOUT ANOTHER FUNCTION OX", "CURRENCY NAME FOB", "US Dollar", "TYPE OF OPERATION DESCRIPTION", "Import for Consumption", "FOB VALUE TOTAL IN US CURENCY", "213177.95999999999", "EXPORTER NAME", "PEPSI-COLA MANUFACTURING CO.OF URUGUAY SRL"
"Date", "Indian Port", "CTH", "Item Description", "Quantity", "UQC", "U.P.USD", "FOB USD", "Destination Port", "Country", "Duty", "23-Nov-2016", "tughlakabad", "piston rings ", "96 ", "NOS ", "4.78 ", "459.29 ", "colombo ", "23-Nov-2016", "tughlakabad", "piston ring- tractor spare parts ", "996 ", "SET ", "1.59 ", "1580.37 ", "yangon ", "23-Nov-2016", "tughlakabad", "piston rings ", "696 ", "NOS ", "3.04 ", "2115.84 ", "bandar abbas ", "23-Nov-2016", "tughlakabad", "piston rings ", "400 ", "NOS ", "3.10 ", "1240.00 ", "bandar abbas ", "23-Nov-2016", "tughlakabad", "piston rings ", "168 ", "NOS ", "46.52 ", "7815.83 ", "hamburg ", "23-Nov-2016", "tughlakabad", "piston rings ", "63 ", "NOS ", "175.47 ", "11054.58 ", "hamburg ", "23-Nov-2016", "nhava sheva sea", "motor vehicle spare parts a.c. piston ring kit ", "15 ", "PCS ", "14.56 ", "218.40 ", "durban ", "23-Nov-2016", "nhava sheva sea", "motor vehicle spare parts a.c. piston kit ", "15 ", "PCS ", "14.02 ", "210.30 ", "durban ", "23-Nov-2016", "mundra", "piston ring (parts suitable for use solely or principally with the engines) (asper invoice) ", "20 ", "SET ", "79.90 ", "1598.00 ", "durban ", "23-Nov-2016", "ludhiana", "diesel engine spare parts piston ring 102mm 3+2 tc 3171cp ", "274 ", "KGS ", "10.79 ", "2956.20 ", "mersin "
对于上述两种格式的数据分别进行抽取整理：
import re
f = open("seair.json", 'r')
data1 = open("data1.txt", 'ab')
for line in f:
subLine = re.sub(r'("Argentina Import Sample [0-9]+", )', '', line)
searchObj = re.findall( r'(IMPORTER NAME.*?"PAYMENT VALUE_USD6", ".*?")', subLine, re.M|re.I )
for item in searchObj:
item = item[0:-1]
writeLine = '{'
sp = item.split('", "')
for i in range(0, len(sp), 2):
if i == len(sp) - 1:
break
if sp[i] == 'IMPORTER NAME ' and writeLine != '{':
writeLine = writeLine[0:-2] + '}\n'
data1.write(writeLine)
writeLine = '{"IMPORTER NAME": '
else:
writeLine = writeLine + "\"" + sp[i] + "\": "
if re.match(r'\A([0-9]+(\.[0-9]+)?)\Z', sp[i + 1], re.M|re.I):
writeLine = writeLine + sp[i + 1] + ', '
else:
writeLine = writeLine + "\"" + sp[i + 1] + "\", "
writeLine = writeLine[0:-2] + '}\n'
data1.write(writeLine)
f.close()
data1.close()
import re
f = open("seair.json", 'r')
data2 = open("data2.txt", 'ab')
count = 0
for line in f:
searchVol = re.findall(r'"hd": \["(Date".*?)", "[0-9]{2}-[a-yA-S]{3,4}-[0-9]{4}', line, re.M|re.I)
searchItem = re.findall(r'([0-9]{2}-[a-yA-S]{3,4}-[0-9]{4}.*)]', line, re.M|re.I)
if len(searchVol) == 0:
continue
spVol = searchVol[0].replace('"CTH", ', '').replace(', "Country", "Duty', '').replace(', "C O O", "Duty', '').split('", "')
spItem = searchItem[0].split('", "')
volNum = len(spVol)
itemNum = len(spItem)
for i in range(itemNum):
if i % volNum == 0:
writeLine = '{'
if len(re.findall(r'([0-9]{2}-[a-yA-S]{3,4}-[0-9]{4})', spItem[i])) == 0:
break
writeLine = writeLine + "\"" + spVol[i % volNum] + "\": "
if re.match(r'\A([0-9]+(\.[0-9]+)?)\Z', spItem[i], re.M|re.I):
writeLine = writeLine + spItem[i] + ', '
else:
writeLine = writeLine + "\"" + spItem[i] + "\", "
if i % volNum == volNum - 1:
writeLine = writeLine[0:-2] + '}\n'
data2.write(writeLine)
count += 1
print count
f.close()
data2.close()
共计整理出59w条数据，观测到数据的重复现象，需去重。鉴于python的set的元素具有唯一性，set在cpython解释器的实现用了hashtable，效率奇高，可用来去重：
#coding=utf-8
import sys, re, os
def getDictList(dict):
regx = '\{.*\}'
with open(dict) as f:
data = f.read()
return re.findall(regx, data)
def rmdp(dictList):
return list(set(dictList))
def fileSave(dictRmdp, out):
with open(out, 'a') as f:
for line in dictRmdp:
f.write(line + '\n')
def main():
try:
dict = sys.argv[1].strip()
out = sys.argv[2].strip()
except Exception, e:
print 'error:', e
me = os.path.basename(__file__)
print 'usage: %s <input> <output>' %me
print 'example: %s dict.txt dict_rmdp.txt' %me
exit()
dictList = getDictList(dict)
dictRmdp = rmdp(dictList)
fileSave(dictRmdp, out)
if __name__ == '__main__':
main()
最后清理得到45w条交易数据
