python

Using set in Python inside a loop

I have the following list in Python: [[1, 2], [3, 4], [4, 6], [2, 7], [3, 9]] I want to group them into [[1,2,7],[3,4,6,9]] My code to do this looks like this: l=[[1, 2], [3, 4], [4, 6], [2, 7], [3, 9]] lf=[] for li in l: for lfi in lf: if lfi.intersection(set(li)): lfi=lfi.union(set(li)) break ...

Python PyQt Timer Firmata

Hello. I am pretty new to python and working with firmata I am trying to play around with an arduino . Here is what I want to happen: Set arduino up with an LED as a digital out Set potentiometer to analog 0 Set PyQt timer up to update potentiometer position in application Set a threshold in PyQt to turn LED on (Analo...

Creating Read-only logs with python

I am writing a python script that needs to make a log entry whenever it's invoked. The log created by the script must not be changeable by the user (except root) who invoked the script. I tried the syslog module and while this does exactly what I want in terms of file permissions, I need to be able to put the resulting log file in an arb...

Setting an class attribute with a given name in python while defining the class

I am trying to do something like this: property = 'name' value = Thing() class A: setattr(A, property, value) other_thing = 'normal attribute' def __init__(self, etc) #etc.......... But I can't seem to find the reference to the class to get the setattr to work the same as just assigning a variable in the class definition. ...

Generate unique hashes for django models

I want to use unique hashes for each model rather than ids. I implemented the following function to use it across the board easily. import random,hashlib from base64 import urlsafe_b64encode def set_unique_random_value(model_object,field_name='hash_uuid',length=5,use_sha=True,urlencode=False): while 1: uuid_number = str(ra...

What algorithms are suitable for this simple machine learning problem?

I have a what I think is a simple machine learning question. Here is the basic problem: I am repeatedly given a new object and a list of descriptions about the object. For example: new_object: 'bob' new_object_descriptions: ['tall','old','funny']. I then have to use some kind of machine learning to find previously handled objects that h...

Django OpenID django-openid-auth Login Error.

I get the following error when attempting to use django-openid-auth OpenID discovery error: No usable OpenID services found for *******@gmail.com I have followed the instructions that come with it, though it seems there is something I am missing. the installation is on my localhost. ...

QTreeWidget insertTopLevelItem - index given not accurately displayed in Tree?

I am unable to properly insert a QTreeWidgetItem at a specific index, in this case I am removing all QTreeWidgetItems from the tree, doing a custom sort on their Date Objects and then inserting them back into the QTreeWidget. However, upon inserting (even one at a time) the QTreeWidgetItem is not inserted into the correct place. The ...

Python OSError not reporting errors

Ive got this snippet that Im using to convert image files to tiff. I want to be informed when a file fails to convert. Imagemagick exits 0 when successfully run, so I figured the following snippet would report the issue. However no errors are being reported at all. def image(filePath,dirPath,fileUUID,shortFile): try: os.sy...

mongokit and django

I'm looking for good tutorial or really simple code to integrate mongokit and django ...

Check if Django model field choices exists

I'm attempting to check if a value exists in the choices tuple set for a model field. For example lets say I have a Model like this: class Vote(models.Model): VOTE_TYPE = ( (1, "Up"), (-1, "Down"), ) value = models.SmallIntegerField(max_length=1, choices=VOTE_TYPES) Now lets say in a view I have a variable new_value = 'Up' t...

Python Amara package does not install with Bindery

I've installed virtualenv in the home directory of a shared university server so that I can install custom packages I need for my application (SQLAlchemy and Amara, most importantly). SQLAlchemy works just fine, but Amara (2.0a4) refuses to cooperate. For some reason, using the virtual environment's easy_install amara command, the Binde...

Django templates crashes with no sense

Hello I'm trying to use google visualization API along with django templates system. I got an error that don't know how to fix. The error is the following: invalid_block_tag raise self.error(token, "Invalid block tag: '%s'" % command) django.template.TemplateSyntaxError: Invalid block tag: 'endfor' The code is: function drawChar...

How do you throw an HTTP error with mod_python

I have a setup where I'm serving simple python pages using the mod_python publisher. At some points I'd like to have the python function raise a standard apache error - for example throwing a 500 error if a required file is missing. How can I throw an apache error from within a mod_python script? ...

How to flush the input stream in python?

I'm writing a simple alarm utility in Python. #!/usr/bin/python import time import subprocess import sys alarm1 = int(raw_input("How many minutes (alarm1)? ")) while (1): time.sleep(60*alarm1) print "Alarm1" sys.stdout.flush() doit = raw_input("Continue (Y/N)?[Y]: ") print "Input",doit if doit == 'N' or doit==...

Query for model by key

What I'm trying to do is query the datastore for a model where the key is not the key of an object I already have. Here's some code: class User(db.Model): partner = db.SelfReferenceProperty() def text_message(self, msg): user = User.get_or_insert(msg.sender) if not user.partner: # user doesn't have a partner, find ...

Purpose of Zope Interfaces?

I have started using Zope interfaces in my code, and as of now, they are really only documentation. I use them to specify what attributes the class should possess, explicitly implement them in the appropriate classes and explicitly check for them where I expect one. This is fine, but I would like them to do more if possible, such as actu...

Getting BeautifulSoup to find a specific <p>

I'm trying to put together a basic HTML scraper for a variety of scientific journal websites, specifically trying to get the abstract or introductory paragraph. The current journal I'm working on is Nature, and the article I've been using as my sample can be seen at http://www.nature.com/nature/journal/v463/n7284/abs/nature08715.html....

Avoid IF statement after condition has been met

I have a division operation inside a cycle that repeats many times. It so happens that in the first few passes through the loop (more or less first 10 loops) the divisor is zero. Once it gains value, a div by zero error is not longer possible. I have an if condition to test the divisor value in order to avoid the div by zero, but I am w...

Proper way to set object instance variables

I'm writing a class to insert users into a database, and before I get too far in, I just want to make sure that my OO approach is clean: class User(object): def setName(self,name): #Do sanity checks on name self._name = name def setPassword(self,password): #Check password length > 6 characters ...