Hi,
Fastest way to uniqify a list in Python without preserving order? I saw many complicated solutions on Internet - could they be faster then simply:
list(set([a,b,c,a]))
?
how can I use wild cars like '*' when getting a list of files inside a directory in Python? for example, I want something like:
os.listdir('foo/*bar*/*.txt')
which would return a list of all the files ending in .txt in directories that have bar in their name inside of the foo parent directory.
how can I do this?
thanks.
I wrote PyQt application. After it's start I close it (GUI), but timer don't stops and Python sometimes freezes. Only thing to unfreeze it - Ctrl-C, after which following message appears:
Traceback (most recent call last):
File "", line 262, in timerEvent
KeyboardInterrupt
timer don't stops again, and CPython works very slowly. How to avoid this problem?
I'm looking for a way in python to find out which type of file system is being used for a given path. I'm wanting to do this in a cross platform way. On linux I could just grab the output of df -T but that won't work on OSX or windows.
In Javascript I can do this:
function A(x) { return x || 3; }
This returns 3 if x is a "non-truthful" value like 0, null, false, and it returns x otherwise. This is useful for empty arguments, e.g. I can do A() and it will evaluate as 3.
Does Python have an equivalent? I guess I could make one out of the ternary operator a if b else c but was wondering what people use for this.
I have a question about idioms and readability, and there seems to be a clash of Python philosophies for this particular case:
I want to build dictionary A from dictionary B. If a specific key does not exist in B, then do nothing and continue on.
Which way is better?
try:
A["blah"] = B["blah"]
except KeyError:
pass
or
if "blah" in B:
A["blah"] = B["blah"]
"Do and ask for forgiveness" vs. "simplicity and explicitness".
Which is better and why?
how to traverse a binary decision tree using python language.
given a tree,i want know how can we travesre from root to required leaf
the feature of the required leaf are given in an dictionary form assume and have to traverse from root to leaf answering the questions at each node with the details given in feature list..
the decision tree node has format ((question)(left tree)(right tree))
while traversing it should answer question at each node and an choose left or right and traverse till leaf?
How are lists in python stored internally? Is it an array? A linked list? Something else?
Or does the interpreter guess at the right structure for each instance based on length, etc.
If the question is implementation dependent, what about the classic CPython?
I am creating a sort of "Command line" in Python. I already added a few functions, such as changing login/password, executing, etc., But is it possible to browse files in the directory that the main file is in with a command/module, or will I have to make the module myself and use the import command? Same thing with changing directories to view, too.
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.
Is there a general convention about exposing members in Python classes? I know that this is a case of "it depends", but maybe there is a rule of thumb.
Private member:
class Node:
def __init__(self):
self.__childs = []
def add_childs(self, *args):
self.__childs += args
node = Node()
node.add_childs("one", "two")
Public member:
class Node2:
def __init__(self):
self.childs = []
node2 = Node2()
node2.childs += "one", "two"
Hi,
I need to compare two files and redirect the different lines to third file. I know using diff command i can get the difference . But, is there any way of doing it in python ? Any sample code will be helpful
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.
im trying to build android from source on ubuntu 10.04. when i enter the repo command:
repo init -u git://android.git.kernel.org/platform/manifest.git -b eclair
it get this error back
exec: 23: python: not found
any ideas.
Contents of check.py:
from multiprocessing import Process
import time
import sys
def slp():
time.sleep(30)
f=open("yeah.txt","w")
f.close()
if __name__=="__main__" :
x=Process(target=slp)
x.start()
sys.exit()
In windows 7, from cmd, if I call python check.py, it doesn't immediately exit, but instead waits for 30 seconds. And if I kill cmd, the child dies too- no "yeah.txt" is created.
How do I make ensure the child continues to run even if parent is killed and also that the parent doesn't wait for child process to end?
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?
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
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.
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 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?
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
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.