I've seen there are actually two (maybe more) ways to concatenate lists in Python: One way is to use the extend() method: a = [1, 2] b = [2, 3] b.extend(a) the other to use the plus(+) operator: b += a Now I wonder: Which of those two options is the 'pythonic' way to do list concatenation and is there a difference between the two (...
I have a simple URLField in my model link = models.URLField(verify_exists = False, max_length = 225) I would like to strip the leading and trailing spaces from the field. I don't think I can do this in "clean_fieldname" or in the "clean" method. Do I need to sub-class the "URLField" and remove the spaces in to_python method? Is ther...
For instance, if I wanted to cycle through a list and perform some operation on all but the final list entry, I could do this: z = [1,2,3,4,2] for item in z: if item != z[-1]: print z.index(item) But instead of getting the output "...0 1 2 3," I'd get "...0 2 3." Is there a way to perform an operation on all but t...
I have a model MyModel that has a field expiration_datetime. Every time a user retrieves an instance of MyModel I need to first check if it has expired or not. If it has expired, than I need to increment some counter, update others, and then extend the expiration_datetime to some time in the future. So the view would do something ...
I'm trying to store an object reference in the rows of a treemodel so that I can access and modify the data in the underlying data structure. What would be the proper way to do this? The only way I've found so far to accomplish this is to inherit my data structure nodes from gobject, and then store a gobject column in each row. Is there ...
If you have a int and you wish to convert it to a single char string you can use the function chr() Is there a way to convert an int to a single char binary stream? e.g: >>> something(97) b'a' What is the something? ...
Hi, how good this python code ? need criticism) there is a error in this code, some times script do print "ALL WAIT - CAN FINISH!" and freeze (no more actions are happend..) but i can't find reason why this happend? site crawler with threadpool: import sys from urllib import urlopen from BeautifulSoup import BeautifulSoup, SoupStrainer...
Here's what I've got: from sqlalchemy import * from sqlalchemy.orm import * from web.models.card import * connectionString = "postgresql://www:www@localhost/prod" databaseEngine = create_engine(connectionString) sessionFactory = sessionmaker(autoflush = True, autocommit = False, bind = databaseEngine) session = sessionFactory() CardsCo...
I've started integrating doctests into my modules. (Hooray!) These tend to be files which started as scripts, and are now are a few functions with CLI apps in the __name__=='__main__', so I don't want to put the running of the tests there. I tried nosetests --with-doctest, but get lots of failures I don't want to see, because some of ...
What are the best Python projects to study if one wants to look at the codebase and see how well-designed Python projects are structured and coded? Open source is preferred for obvious reasons, but they could be closed-source too. It could be interesting to see how the interface or API is designed. Small projects would be as interestin...
new one to me commend I'm running ubuntu 10.04 relatively fresh install on my laptop manually installed django 1.2.1 when I try to run inside of a virtualenv python manage.py **any command** I get the error "bash: /home/alvin/workspace/storm-guard/virtual_damage_restoration/bin/python: cannot execute binary file " I have done the fo...
I need to create a numpy 2D array which represents a binary mask of a polygon, using standard Python packages. input: polygon vertices, image dimensions output: binary mask of polygon (numpy 2D array) (Larger context: I want to get the distance transform of this polygon using scipy.ndimage.morphology.distance_transform_edt.) Can any...
I am making a change program in python. The user must input a dollar amount and then the program will calculate the change in twenties, tens, fives, ones, quarters, dimes, nickels, and pennies. I was instructed to use the round function for the pennies because If I input an amount of $58.79, the program tells me to give 3 pennies back w...
I've got PyDev installed in Eclipse. I'm trying to play with Django. I'm got a remote MySQL database set up. I would really like to not install MySQL on my MacBook. Trying to set up the MySQL plugin for python, I get (djangotest)jeebus:MySQL-python-1.2.3 blah$ python setup.py clean sh: mysql_config: command not found Traceback (most r...
Is there an out of the box way to format in python (or within django templates), a date with full month name in accordance to polish language rules? I want to get: 6 września 2010 and not: >>> datetime.today().date().strftime("%d %B %Y") '06 wrzesień 2010' ...
Hi all, I'm trying to make django work on snow leopard. So far I've installed mysql 64 bit installed python 2.7 64 bit and installed django 1.2.1. Now I'm trying to install mysql-python-1.2.3; at the beginning I had problems because I hadn't installed the setup tool, having done that when try to install it by executing these command pyt...
Say I have a fabfile.py that looks like this: def setup(): pwd = getpass('mysql password: ') run('mysql -umoo -p%s something' % pwd) The output of this is: [host] run: mysql -umoo -pTheActualPassword Is there a way to make the output look like this? [host] run: mysql -umoo -p******* Note: ...
I've got a Matplotlib graph with two y axes, created like: ax1 = fig.add_subplot(111) ax1.grid(True, color='gray') ax1.plot(xdata, ydata1, 'b', linewidth=0.5) ax2 = ax1.twinx() ax2.plot(xdata, ydata2, 'g', linewidth=0.5) I need grid lines but I want them to apply to both y axes not just the left one. The scales of each axes will diffe...
I've been experimenting with embedding different scripting languages in a C++ application, currently I'm trying Stackless Python 3.1. I've tried several tutorials and examples, what few I can find, to try and run a simple script from an application. Py_Initialize(); FILE* PythonScriptFile = fopen("Python Scripts/Test.py", "r"); if(Pyth...
Basically I want to know why this works: class MyClass: pass myObj = MyClass() myObj.foo = 'a' But this returns an AttributeError: myObj = object() myObj.foo = 'a' How can I tell which classes I can use undefined attributes with and which I can't? Thanks. ...