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]))
?
I downloaded a webpage in my python script.
In most cases, this works fine.
However, this one had a response header: GZIP encoding, and when I tried to print the source code of this web page, it had all symbols in my putty.
How do decode this to regular text?
I am creating an application that lets users login using Google, Facebook and the website's native login. The site is being built in Python / Django.
What would be the best way to handle login, session management and user authentication?
I do not want to use the in-built Django user management. I am using Django very sparingly(URLs, templates)
The greenlet package is used by gevent and eventlet for asynchronous IO. It is written as a C-extension and therefore doesn't work with Jython or IronPython. If performance is of no concern, what is the easiest approach to implementing the greenlet API in pure Python.
A simple example:
def test1():
print 12
gr2.switch()
print 34
def test2():
print 56
gr1.switch()
print 78
gr1 = greenlet(test1)
gr2 = greenlet(test2)
gr1.switch()
Should print 12, 56, 34 (and not 78).
Format is like:
CHINA;2002-06-25 00:00:00.000;5,60
CHINA;2002-06-26 00:00:00.000;5,32
CHINA;2002-06-27 00:00:00.000;5,31
and I try to use Python's CSV tools to parse it but cannot understand the paragraph, source:
And while the module doesn’t directly support parsing strings, it can easily be done:
import csv
for row in csv.reader(['one,two,three']):
print row
Could someone clarify the line ['one,two,three']? How would you use it with format A;B;C?
Using python and wsgiref.handlers, I can get a single variable from a form with self.handler.request.get(var_name), but how do I iterate through all form variables, be they from GET and POST? Is it something like this?
for field in self.handler.request.fields:
value = self.handler.request.get(field)
Again, it should include both fields included in the POST and fields from the query string, as in a GET request.
Thanks in advance folks...
Hi,
I am planning to write a generic python module for installing a package. This script should retrieve the module from a remote machine or locally and install it on a given host and user. However, there needs to be changes made to the package files based on the host, user and given environment.
My approach is to use XML to describe changes to be made to package files based on environment. It will first extract the package to the user directory and then using an xml configuration file, it should replace the file values in the package directory. The xml would look something like this:
<package version="1.3.3">
<environment type="prod">
<file dir="d1/d2" name="f1">
<var id="RECV_HOST" value="santo">
<var id="RECV_PORT" value="RECV_PORT_SERVICE" type="service">
<var id="JEPL_SERVICE_NAME" value="val_omgact">
</file>
<var dir="d4/d3/s2" name="f2">
<var id="PRECISION" value="true">
<var id="SEND_STATUS_CODE" value="323">
<var id="JEPL_SERVICE_NAME" value="val_omgact">
</file>
</environment>
<environment type="qa">
<file dir="d1/d2" name="f1">
<var id="RECV_HOST" value="test">
<var id="RECV_PORT" value="1444">
<var id="JEPL_SERVICE_NAME" value="val_tsdd">
</file>
<file dir="d4/d3/s2" name="f2">
<var id="PRECISION" value="false">
<var id="SEND_STATUS_CODE" value="323">
<var id="JEPL_SERVICE_NAME" value="val_dsd">
</file>
</environment>
</package>
What are your thoughts on this approach? Is there an existing python module, package or script that I could use for this purpose since this seems fairly generic and can be used for any installation.
Thanks!
Sam
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?
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?
Hi
I am trying to perform a 2d convolution in python using numpy
I have a 2d array as follows with kernel H_r for the rows and H_c for the columns
data = np.zeros((nr, nc), dtype=np.float32)
#fill array with some data here then convolve
for r in range(nr):
data[r,:] = np.convolve(data[r,:], H_r, 'same')
for c in range(nc):
data[:,c] = np.convolve(data[:,c], H_c, 'same')
It does not produce the output that I was expecting, does this code look OK
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"
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.
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.
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?
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.
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 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.
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 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
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.
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")
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?