Parsing feeds - part 1

From time to time I used conky. Is good for me, because i have all i need on my desktop.
How helped me python in this case?
For example i use one script to parse a feed from this url:
"http://www.bnro.ro/nbrfxrates.xml"
The example is simple to understand :

from xml.dom import minidom as dom
import urllib
def fetchPage(url):
a = urllib.urlopen(url)
return ''.join(a.readlines())

def extract(webpage):
a = dom.parseString(webpage)
item2 = a.getElementsByTagName('SendingDate')[0].firstChild.wholeText
print "DATA ",item2
item = a.getElementsByTagName('Cube')
for i in item:
if i.hasChildNodes() == True:
eur = i.getElementsByTagName('Rate')[10].firstChild.wholeText
dol = i.getElementsByTagName('Rate')[26].firstChild.wholeText
print "EURO  ",eur
print "DOLAR ",dol

if __name__=='__main__':
webpage = fetchPage("http://www.bnro.ro/nbrfxrates.xml")
extract(webpage)

The result is:

$python xmlparse.py
DATA  2010-02-04
EURO   4.1214
DOLAR  2.9749

With "urllib" package I read the url.
The result is parsing with functions from "dom" package.
I used this functions "parseString" and "getElementsByTagName".
More about this functions you will see on:
http://docs.python.org/library/xml.dom.minidom.html
This is all.

How to resize images .

Sometimes it is necessary to resize the images. The PIL module is used for image processing.The glob module takes a wildcard and returns the full path of all files and directories matching the wildcard.
Here are two scripts that I made.
The first is a simple example using a resize after some dimensions.
In this case we used size 300x300.

from PIL import Image
import glob, os
size_file = 300,300
for f in glob.glob("*.png"):
   file, ext = os.path.splitext(f)
   img = Image.open(f)
   img.thumbnail(size_file, Image.ANTIALIAS)
   img.save("thumb_" + file, "JPEG")

In the second case I tried to do a resize with proportion preservation.

import glob 
import PIL
from PIL import Image
for f in glob.glob("*.jpg"):
 img = Image.open(f)
 dim_percent=(100/float(img.size[0]))
 dim_size=int((float(img.size[1])*float(dim_percent)))
 img = img.resize((100,dim_size),PIL.Image.ANTIALIAS)
 if f[0:2] != "trumb_":
  img.save("thumb_" + f, "JPEG")

In both cases we use a renaming of files by adding the name of "thumb_".
Ambele scripturi pot fi modificate asa cum vreti.
Aceste scripturi demonstreaza cum sa folosim celor doua module "PIL" si "globe".

New book for kids with Python 3

Few days ago i found a new site about python .
I saw on this site the a new book about python for kids .
This is the link "Snake Wrangling for Kids".
The author says:

• “Snake Wrangling for Kids” is a printable electronic book, for children 8 years and older, who would like to learn computer programming. It covers the very basics of programming, and uses the Python 3

GTK - get display resolution

Sometime is need to get the display resolution.
This python code show how to do it:

>>> import gtk
>>> dgd=gtk.gdk.display_get_default()
>>> gsd=dgd.get_default_screen()
>>> height=gsd.get_height()
>>> width=gsd.get_width()
>>> print "height=",height,"width=",width
height= 1024 width= 1280

Quite simply ...

MD5 - password generator

Why do we need this script?
Internet is full of generating MD5.
The Internet has and dictionaries for decrypting md5.
So safe is our script.
You must use the code line:

p = md5.new ()

otherwise if you use:

pass = md5.new ()

you get the following error:

>>> pass = md5.new()
File "", line 1
pass = md5.new()
^
SyntaxError: invalid syntax

pass is a python keyword.
You'll need a different name for the variable.
And now to see the code:

import md5 
p = md5.new()
p.update("password")
p.hexdigest()
'5f4dcc3b5aa765d61d8327deb882cf99'

This is all you need.

Pyglet - simple example

First i wanted to make a simple example. Then I saw George Oliver googlegrups question. This made me change my little script.Official Site address is: www.pyglet.org.
Documentation of this module is to: www.pyglet.org/documentation.html.
There is also a Google group for this mode where you can ask questions.
My example does nothing more than:
- Create a fereasta;
- To put a background color;
- Displaying an image.
Image i use it, name it "20000.jpg" is this:

Put in folder with your script.
In the future I will come with more complex examples.
Change the following sequence of lines of code example:

  win.clear ()
  img1.blit (5, 5)

You will see that the order matters for pyglet.
Who studied OpenGL knows why.

import pyglet
from pyglet.gl import *
#set colors with red,green,blue,alpha values 
colors = {
            'playfield' : (255, 255, 255, 255),
            'red' :       (255, 0, 0, 255,0),
            'sub_red' :   (255, 50, 20, 255),
            'green' :     (0, 255, 0, 255),
            'sub_green' : (20, 255, 50, 255),
            'blue' :      (0, 0, 255, 255),
            'sub_blue' :  (20, 50, 255, 255)} 
#give img1 the place of image 
img1= pyglet.image.load('20000.jpg')
#w , h the size of image 
w = img1.width+15
h = img1.height+10
# create the 640x480 window size
win = pyglet.window.Window(640, 480, resizable=True, visible=True)
#or use next line to see with size of image 
#win=pyglet.window.Window(width=w, height=h)

# set caption of window
win.set_caption("TEST")
#use * to unpack tuple and set background color 
pyglet.gl.glClearColor(*colors['red'])

@win.event

def on_draw():
 win.clear()
 img1.blit(5, 5)
# to run application 
pyglet.app.run()

If you use the code line:

win = pyglet.window.Window(640, 480, resizable=True, visible=True)

you see:

If you use the code line:

win=pyglet.window.Window(width=w, height=h)

you see:

Random words from lists and text

Sometimes it is necessary to choose random words from lists or texts.
Example below illustrates this:

import random
list_input = """ Apple
 Crabapple
 Hawthorn
 Pear
 Apricot
""".strip().split("\n")
text_input = "This is a text without newline char".split()
print "List is =", list_input
print "---------------------------------------"
list_result = random.choice(list_input)
print "Random list result is =", list_result
print "---------------------------------------"
print "Text is =", text_input
print "---------------------------------------"
text_result = random.choice(text_input)
print "Random word result is =", text_result

We have two variables "list_input" and "text_input" containing a list of words separated by newline char and a simple string ending in newline char.
Its separation is made with function ".strip ()" .
This function separates the items in the list after this particular bracket expression. The result of the expression in brackets vanishes from the list.
The result of scripts is :

List is = ['Apple', ' Crabapple', ' Hawthorn', ' Pear', ' Apricot']
---------------------------------------
Random list result is =  Pear
---------------------------------------
Text is = ['This', 'is', 'a', 'text', 'without', 'newline', 'char']
---------------------------------------
Random word result is = is

How to use "try" ... "except"

Any program will be given over to error checking.
Python provides an exception handling capability.
There are two parts : "error checking" "catching exceptions".
Now let's try a simple example:

>>> try :
...     input_str = int(input ("string "))
... except StandardError :
...     print " This is not a number"
... 
string 12
>>> try :
...     input_str = int(input ("string "))
... except StandardError :
...     print " This is not a number"
... 
string aaa
 This is not a number

The code :

input_str = int(input ("string "))

The code readed input will be convert in integer .
If types a value that's not an integer, the exception is caught.
In this case will print " This is not a number ".
This is very important because it generates more errors while running a program.
So, simply try to perform you action, and define what's to be done.
On except block if the action you want can't be completed.

Permutation of chars with python

It is a simple example of using python language to permutation of chars.
It uses a list generator and "yield":

#!/usr/bin/env python
def permut(lst):
    remove = lambda lst0, index: lst0[:index] + lst0[index+1:]
    if lst:
        for index, x in enumerate(lst):
            for y in permut(remove(lst, index)):
                yield (x,)+y
            print y 
                
    else: yield ()
lst='catalin'
for p in permut(['c','a','t','a','l','i','n']):
    print p

Example can be modified so output will be a file.

Google and Python Stuff

I want share this scripts.
Is just two scripts and i think is beautifull.
First is a youtube script :

import gdata.youtube
import gdata.youtube.service

client_yt = gdata.youtube.service.YouTubeService()
query = gdata.youtube.service.YouTubeVideoQuery()
query.vs = "%s" % ('News')
feed = client_yt.YouTubeQuery(query)

for entry in feed.entry:
print entry.title.text
for link in entry.link:
if link.rel == 'alternate':
print link.href

Second is a picassa script :

import gdata.photos
import gdata.photos.service
import urllib
p_client = gdata.photos.service.PhotosService()

query_parameters = map(urllib.quote, ['Sexy','Bucharest']);
feed = p_client.GetFeed("/data/feed/api/all?q=%s%s&max-results=10" % ('Sexy','Girl'))

for entry in feed.entry:
print entry.title.text
for link in entry.link:
if link.rel == 'alternate':
print link.href

I hope you like this little scripts.

Sqlite and Python

These script explore the Python Sqlite modules available for database administration.
Sometime you need to use extraction, processing, storage and presentation of your data.
This is a short example :

#!/usr/bin/python

import sqlite3

def select_db():
print "Select database"

co=sqlite3.connect("cata2.db")
cursor=co.execute("CREATE TABLE report (nr INT,user VARCHAR(20),descriere VARCHAR(100));")
cursor=co.execute("INSERT INTO report (nr,user,descriere) VALUES (1,'root','root administration');")
cursor=co.execute("SELECT * FROM report;")

print cursor.fetchall()

This python script will be create cata.db file on your folder.
The table of database is 'report' and add next values "1,'root','root administration'".
If you want create new database , use :

co=sqlite3.connect("new_database.db")
cursor=co.execute("CREATE TABLE tabela (some_value_integer INT,some_value_chars VARCHAR(20));")

If you want show it , use this :

cursor=co.execute("SELECT * FROM new_database;")

Thank you !

resize images to create thumbnails

First you have many images.
If you want to create thumbnail for each one this is python script:

import glob 
import PIL
from PIL import Image
for infile in glob.glob("*.jpg"):
 img = Image.open(infile)
 dim_percent=(100/float(img.size[0]))
 dim_size=int((float(img.size[1])*float(dim_percent)))
 img = img.resize((100,dim_size),PIL.Image.ANTIALIAS)
 if infile[0:2] != "trumb_":
  img.save("trumb_" + infile, "JPEG")

PyGTK and GdkPixbuf

What is GdkPixbuf?
* An object holding information about images in memory.
Constructor
GdkPixbuf (GdkColorspace colorspace, bool has_alpha, int bits_per_sample, int width, int height);

Example:

>>> import pygtk
>>> import pygtk
>>> pixbuf = gtk.gdk.Pixbuf( gtk.gdk.COLORSPACE_RGB, False,8, 200, 100)
>>> pixbuf.save('/home/net/cc/a.jpg','jpeg', {'quality':'100'})

The output is :