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Archive for December, 2010

Where does a page redirect to?

December 21, 2010 Leave a comment

Question

We have a page that redirects to another page. How to figure out where the redirection points to?

Answer

import urllib

s = "https://pythonadventures.wordpress.com?random"    # returns a random post
page = urllib.urlopen(s)
print page.geturl()    # e.g. http:// pythonadventures.wordpress.com/2010/10/08/python-challenge-1/

Credits

I found it in this thread.

Update (20121202)

With requests:

>>> import requests
>>> r = requests.get('https://pythonadventures.wordpress.com?random')
>>> r.url
u'https://pythonadventures.wordpress.com/2010/09/30/create-import-module/'
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Categories: python Tags: , ,

unicode to ascii

December 17, 2010 Leave a comment

Problem

I had the following unicode string: “Kellemes √únnepeket!” that I wanted to simplify to this: “Kellemes Unnepeket!”, that is strip “√ú” to “U”. Furthermore, most of the strings were normal ascii, only some of them were in unicode.

Solution

import unicodedata

title = ...   # get the string somehow
try:
    # if the title is a unicode string, normalize it
    title = unicodedata.normalize('NFKD', title).encode('ascii','ignore')
except TypeError:
    # if it was not a unicode string => OK, do nothing
    pass

Credits

I used the following resources:

Categories: python Tags: , , ,

Using MySQL from Python

December 14, 2010 Leave a comment

Problem

You want to interact with a MySQL database from your Python script.

Solution

First of all, you need to install the following package:

sudo apt-get install python-mysqldb

Then try the following basic script to check if everything is OK:

#!/usr/bin/env python

import MySQLdb

conn = MySQLdb.connect (host = "localhost",
                        user = "testuser",
                        passwd = "testpass",
                        db = "test")
cursor = conn.cursor ()
cursor.execute ("SELECT VERSION()")
row = cursor.fetchone ()
print "server version: ", row[0]
cursor.close ()
conn.close ()

Example:

We have a .csv file with two columns: symbol and name. Iterate through the lines and insert each line in a database table as a record.

#!/usr/bin/env python

import MySQLdb

f1 = open('./NYSE.csv',  'r')
# A line looks like this:
# ZLC;    Zale Corporation

conn = MySQLdb.connect(host = "localhost",
                       user = "user",
                       passwd = "passwd",
                       db = "table")
cursor = conn.cursor()

for line in f1:
    pieces = map(str.strip, line.split(';'))
    #print "'%s' => '%s'" % (pieces[0], pieces[1])
    query = "INSERT INTO symbol_name (symbol, name) VALUES (\"%s\", \"%s\")" % (pieces[0], pieces[1])
    #print query
    cursor.execute(query)

f1.close()

conn.commit()
cursor.close ()
conn.close ()

Links

There are lots of Python-MySQL tutorials on the net. Let’s see some of them:

Categories: python Tags: