Does anyone know of a memory efficient way to generate very large xml files (e.g. 100-500 MiB) in Python?
I've been utilizing lxml, but memory usage is through the roof.
I have two floats in Python that I'd like to subtract, i.e.
v1 = float(value1)
v2 = float(value2)
diff = v1 - v2
I want "diff" to be computed upto two significant figures, that is compute it using %.2f of v1 and %.2f of v2. How can I do this? I know how to print v1 and v2 up to two decimals, but not how to do arithmetic like that.
thanks.
wow i thought i knew python untill tonight.. what is the correct way to do something like this.. heres my code
a = ["one", "two", "three"]
b = a #here i want a complete copy that when b is changed, has absolutely no effect on a
b.append["four"]
print a #a now has "four" in it..
so basically i want to know, instead of the b = a step, how would i correctly make a copy of a list or dictionary so that when b is changed a does not change along with it.. thanks guys
I have a string of HTML stored in a database. Unfortunately it contains characters such as ®
I want to replace these characters by their HTML equivalent, either in the DB itself or using a Find Replace in my Python / Django code.
Any suggestions on how I can do this?
One of the ideas of Python's design philosophy is "There should be one ... obvious way to do it." (PEP 20), but that can't always be true. I'm specifically referring to (simple) if statements versus boolean evaluation. Consider the following:
if words:
self.words = words
else:
self.words = {}
versus
self.words = words or {}
With such a simple situation, which is preferable, stylistically speaking? With more complicated situations one would choose the if statement for readability, right?
I am running a multithreaded application(Python2.7.3) in a Intel(R) Core(TM)2 Duo CPU E7500 @ 2.93GHz. I thought it would be using only one core but using the "top" command I see that the python processes are constantly changing the core no. Enabling "SHOW THREADS" in the top command shows diffrent thread processes working on different cores.
Can anyone please explain this? It is bothering me as I know from theory that multithreading is executed on a single core.
So the setup is a slew of proprietary server/client Python applications running on one Linux box (the server) and a set of Windows 7 workstations (the clients). Everything is running smoothly until any of the proprietary Python packages needs updating.
For now I am using distutils eggs which are very easily updated with easy_install, but it is still a manual process which quickly becomes tedious as the number of applications and client workstations grow.
The ideal setup IMHO is to have the Python packages on the server so when a client application is launched on a workstation the client application can check to see whether its current Python packages are up-to-date. If not, the client application should download the newer Python package from the server, install it, and then launch as per normal.
Does this sounds familiar to anyone? I have tried to find alternatives myself, but as far as I can see there is no Python module offering this functionality. Does anyone have any home made solutions for this?
Hi
I wrote a matlab code (that easily could be implimented as a function) that convert a series of BMPs to avi. I want a python program to call to this program/function. how do I do it?
thanks
Hi,
I am looking for a python SOAP 1.2 client but it seems that it does not exist . All of the existing clients are either not maintainted or only compatible with SOAP 1.1:
suds
SOAPpy
ZSI
Can we initialize python objects with statement like this:
a = b = c = None
it seems to me when I did a = b = c = list() will cause circular reference count issue.
Please give your expert advice.
Python has string.find() and string.rfind() to get the index of a substring in string.
I wonder, maybe there is something like string.find_all() which can return all founded indexes (not only first from beginning or first from end)?
For example:
string = "test test test test"
print string.find('test') # 0
print string.rfind('test') # 15
#that's the goal
print string.find_all('test') # [0,5,10,15]
Hi folks,
I'm having quite a problem deciding how to serve a few Python scripts.
The problem is that the basic functionality could be generalized by this:
do_something()
time.sleep(3)
do_something()
I tried various WSGI servers, but they have all been giving me concurrency limitations, as in I have to specify how many threads to use and so on.
I only wish that the resources on the server be used efficiently and liberally.
Any ideas?
I want to run:
python somescript.py somecommand
But, when I run this I need PYTHONPATH to include a certain directory. I can't just add it to my environment variables because the directory I want to add changes based on what project I'm running. Is there a way to alter PYTHONPATH while running a script? Note: I don't even have a PYTHONPATH variable, so I don't need to worry about appending to it vs overriding it during running of this script.
Given a PyObject* pointing to a python object, how do I invoke one of the object methods? The documentation never gives an example of this:
PyObject* obj = ....
PyObject* args = Py_BuildValue("(s)", "An arg");
PyObject* method = PyWHATGOESHERE(obj, "foo");
PyObject* ret = PyWHATGOESHERE(obj, method, args);
if (!ret) {
// check error...
}
This would be the equivalent of
>>> ret = obj.foo("An arg")
Windows XP, Python 2.5:
hash('http://stackoverflow.com') Result: 1934711907
Google App Engine (http://shell.appspot.com/):
hash('http://stackoverflow.com') Result: -5768830964305142685
Why is that? How can I have a hash function which will give me same results across different platforms (Windows, Linux, Mac)?
Can you please give me a simple, and straightforward python example of sending an HTML e-mail using App Engine? Plaintext is straightforward, but I'm having difficulties with HTML tags.
I'm using the following code to hide stderr on Linux/OSX for a Python library I do not control that writes to stderr by default:
f = open("/dev/null","w")
zookeeper.set_log_stream(f)
Is there an easy cross platform alternative to /dev/null? Ideally it would not consume memory since this is a long running process.
Cant download any pyhton windows modules and install. I wanted to experiment with scrapy framework and stackless but unable to install due to error "Python veIrsion 2.6 required, which was not found in the registry".
Trying to install it to
Windows 7, 64 bit machine
given a list of python strings, how can I automatically convert them to their correct type? Meaning, if I have:
["hello", "3", "3.64", "-1"]
I'd like this to be converted to the list
["hello", 3, 3.64, -1]
where the first element is a stirng, the second an int, the third a float and the fourth an int.
how can I do this? thanks.
I'm trying to use Emacs as a python editor and it works fine when I evaluate(C-c C-c) only single files but when I evaluate a file that imports another file in the same directory, I get an error saying that the file could not be imported.
Does anyone know of a workaround?
Thanks in advance
Hi,
I was going over some pages from WikiVS, that I quote from:
because lambdas in Python are restricted to expressions and cannot contain statements
I would like to know what would be a good example (or more) where this restriction would be, preferably compared to the Ruby language.
Thank you for your answers, comments and feedback!
I have a system where a central Java controller launches analysis processes, which may be written in C++, Java, or Python (mostly they are C++). All these processes currently run on the same server. What are you suggestions to
Create a central log to which all processes can write to
What if in the future I push some processes to another server. How can I support distributed logging?
Thanks!
Hi,
I was wondering if there is a way to automatically run commands on entering the python shell as you would with the .bash_profile or .profile scripts with bash. I would like to automatically import some modules so I don't have to type the whole shebang everytime I hop into the shell.
Thanks,