Where can i find good practice python problems with solutions?
I'm looking for detailed practice problems that are designed with a coding purpose in mind.
I've been using Python for quite a while now, and I'm still unsure as to why you would subclass from object. What is the difference between this:
class MyClass():
pass
And this:
class MyClass(object):
pass
As far as I understand, object is the base class for all classes and the subclassing is implied. Do you get anything from explicitly subclassing from it? What is the most "Pythonic" thing to do?
In Windows the Dropbox client uses python25.dll and the MS C runtime libraries (msvcp71.dll, etc). On OS X the Python code is compiled bytecode (pyc).
My guess is they are using a common library they have written then just have to use different hooks for the different platforms.
What method of development is this? It clearly isn't IronPython or PyObjC. This paradigm is so appealing to me, but my CS foo and Google foo are failing me.
i have users from all timezones, and i want to send out alerts at around 8AM in each users respective timezone.
i need a python script that runs every hour [in a cron job] and i need to find out at which timezone it is 8AM right now, and i can use that info to select the users that have to receive the alerts.
how do i go about doing this? there seems to be gmt+14 to gmt-12 that is 27 timezones, and there are only 24 hours in a day!
want to ask user to input something but not want to wait forever. There is a solution for Linux, http://stackoverflow.com/questions/1335507/keyboard-input-with-timeout-in-python, but I am in windows environment. anybody can help me?
I have a ClassA containing an ArrayList of another ClassB
I can save a new instance of ClassA with ClassB instances also saved using JDO.
However,
When I retrieve the instance of Class A,
I try to do like the below:
ClassA instance = PMF.get().getPersistenceManager().GetObjectByID( someid );
instance.GetClassBArrayList().add( new ClassB(...) );
I get an Exception like the below:
Uncaught exception from servlet com.google.appengine.api.datastore.DatastoreNeedIndexException: no matching index found..
So I was wondering, Is it possible to add a new item to the previously saved collection?
Or was it something I missed out.
Best Regards
All the Python built-ins are subclasses of object and I come across many user-defined classes which are too. Why? What is the purpose of the class object? It's just an empty class, right?
I want to start using Python for small projects but the fact that a misplaced tab or indent can throw a compile error is really getting on my nerves. Is there some type of setting to turn this off?
I'm currently using NotePad++. Is there maybe an IDE that would take care of the tabs and indenting?
Although it does not seem possible, I wanted to put this out there to see if others had some innovative solutions to 'dynamically loading and executing code in python'
So if one saved code in a database, one could read it and 'exec it', however if one wanted to use it in a similar fashion to the filesystem, one would need to
'save and load the compiled .pyc'
create an 'import dbimp' ala 'import imp' etc.
any pointers? ideas? thoughts?
I've got a piece of software which consists of several python sources and a couple of c++ libraries. I'd like to pack them in a executable single file, just like java does with .jar files. Is there a way to do that?
I have a list of elements, and each element consists of four seperate values that are seperated by tabs:
['A\tB\tC\tD', 'Q\tW\tE\tR', etc.]
What I want is to create a larger list without the tabs, so that each value is a seperate element:
['A', 'B', 'C', 'D', 'Q', 'W', 'E', 'R', etc.]
How can I do that in Python? I need it for my coursework, due tonight (midnight GMT) and I'm completely stumped.
I'm parsing some code and want to match the doxygen comments before a function. However, because I want to match for a specific function name, getting only the immediately previous comment is giving me problems.
Is there a way to search backward through a string using the Python Regex library?
Is there a better (easier) approach that I'm missing?
I have a file that I need to "protect" so that it cannot be copied! I am using Python on Windows XP.
I think it may just be changing file permissions??
I'm writing a script to parse some text files, and insert the data that they contain into a mysql database. I don't have root access on the server that this script will run on. I've been looking at mysql-python, but it requires a bunch of dependencies that I don't have available. Is there a simpler way to do this?
Hi,
UserA and UserB are changing objectA.filedA objectA.filedB respectively and at the same time.
Because they are not changing the same field one might think that there are no overlaps.
Is that true?
or the implementation of pm.makePersistnace() actually override the whole object...
good to know...
I was wondering how to make a python script portable to both linux and windows?
One problem I see is shebang. How to write the shebang so that the script can be run on both windows and linux?
Are there other problems besides shebang that I should know?
Is the solution same for perl script?
Thanks and regards!
I am trying to add some security to my computer at home and would like to have a copy of all Yahoo! IMs sent to me. I am using Python 2.6 on Windows.
I would also like to have every URL in Internet Explorer sent to me.
A project that involves image processing, i.e. to calculate the angular shift of the same image when shifted by a medium of certain Refractive Index. We have to build an app that correlates the 2 images (phase/2D correlation?) and then plot using Chaco and Mayavi (2 libraries in Python).
Is there any other existing template software (FOSS) that we can base our app on, or use it as a reference?
In Perl, I would write:
$x = "abbbc";
$x =~ s/(b+)/z/;
print "Replaced $1 and ended up with $x\n";
# "Replaced bbb and ended up with azc"
How do I do this in Python -- do a regular-expression string replacement and record what it was that got replaced?
Is there a way in python without wrapping a function call like following?
from sys import stdout
from copy import copy
tempstdout = copy(stdout)
stdout = file("trash",w)
foo()
stdout = tempstdout
That way works but appears to be terribly inefficient. There has to be a better way... I would appreciate any insight I can get into this.
Why in this millenium should Python PEP-8 specify a maximum line length of 79 characters?
Pretty much every code editor under the sun can handle longer lines. What to do with wrapping should be the choice of the content consumer, not the responsibility of the content creator.
Are there any (legitimately) good reasons for adhering to 79 characters in this age?
I would like to install my python application as a command line tool that should work entirelly inside the install directory (for example C:\Python26\Lib\site-packages\application)
The problem is I would like to reffer in runtime to the submodules and resources from within the application directory three. If I install the app with [console_scripts] option the default path is the current directory. Is there a elegant way to keep the current execution path of the application to the site-packages directory?
Thanks
I usually do this in Perl:
whatever.pl
while(<>) {
#do whatever;
}
then cat foo.txt | whatever.pl
Now, I want to do this in Python. I tried sys.stdin but I have no idea how to do as I have done in Perl. How can I read the input?
Thanks.
EDIT:
Thanks, I like every single solution.
In a python source code I stumbled upon I've seen a small b before a string like in:
b"abcdef"
I know of u prefix that means unicode and r prefix that means raw.
What does the b stand for and in which kind of source code is it useful as it seems to be exactly like a plain string without any prefix ?