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C++ templates that accept only certain types
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I suggest using Boost's static assert feature in concert with is_base_of from the Boost Type Traits library:
template<typename T>
class ObservableList {
BOOST_STATIC_ASSERT((is_base_of<List, T>::value)); //Yes, the double parentheses are needed, otherwise the comma will be seen as...
How exactly do Django content types work?
...Blah blah, let's dive into some code and see what I mean.
# ourapp.models
from django.conf import settings
from django.db import models
# Assign the User model in case it has been "swapped"
User = settings.AUTH_USER_MODEL
# Create your models here
class Post(models.Model):
author = models.Forei...
What does axis in pandas mean?
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I think the confusion comes from the complexity of each so-called "act". df.dropna(axis=0) will first check all the COLUMNS in each ROW and then drop those ROWS with a null. The axis talks about the last step but our brain will focus on the first part....
How do I check what version of Python is running my script?
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From the command line (note the capital 'V'):
python -V
This is documented in 'man python'.
From IPython console
!python -V
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Redirect stdout to a file in Python?
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It doesn't work with from sys import stdout, maybe because it creates a local copy. Also you can use it with with, e.g. with open('file', 'w') as sys.stdout: functionThatPrints(). You can now implement functionThatPrints() using normal print stat...
Programmatically saving image to Django ImageField
...s an image off the web and stores it in a model. The important bits are:
from django.core.files import File # you need this somewhere
import urllib
# The following actually resides in a method of my model
result = urllib.urlretrieve(image_url) # image_url is a URL to an image
# self.photo is ...
Removing all unused references from a project in Visual Studio projects
...thin various Visual Studio versions to automatically remove all references from a project that were never been used?
14 Ans...
When to use self over $this?
...e Y, it calls Y::foo(). But with self::foo(), X::foo() is always called.
From http://www.phpbuilder.com/board/showthread.php?t=10354489:
By http://board.phpbuilder.com/member.php?145249-laserlight
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How to remove leading zeros from alphanumeric text?
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You can use the StringUtils class from Apache Commons Lang like this:
StringUtils.stripStart(yourString,"0");
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How can I tell if I'm running in 64-bit JVM or 32-bit JVM (from within a program)?
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How can you tell from the command line? If you are running 32-bit or 64-bit? Just curious.
– Xonatron
Feb 2 '12 at 20:33
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