使用Python网络抓取下载许多文件

Question

If I have a link to a CSV on Yahoo Finance: http://ichart.finance.yahoo.com/table.csv?s=LOW&d=4&e=29&f=2014&g=d&a=8&b=22&c=1981&ignore=.csv

how would I write a web scraper to download multiple files based on a list of symbols: [LOW, SPY, AAPL]

from StringIO import StringIO 
from urllib2 import urlopen

for symbol in symbols:
    f = urlopen ('http://www.myurl.com'+symbol+'therestoftheurl')
    p = f.read()
    d = StringIO(p)
    f.close

Do I need to write the contents of the url to file, or will it download automatically into a directory?

Answer 1

You can use a method like this to download files:

import urllib2

file_name = "myfile.xyz"
u = urllib2.urlopen(url)
f = open(file_name, 'wb')

block_sz = 4096
while True:
    buffer = u.read(block_sz)
    if not buffer:
        break
    f.write(buffer)

f.close()