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Django Admin - Disable the 'Add' action for a specific model
... need other things, and the 'add model' in the django admin throughs a 500 from a custom queryset.
5 Answers
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What does a tilde do when it precedes an expression?
...f other then-contemporary systems programming languages. It probably stems from the way the hardware works; lots of CPUs set a zero bit after an operation, and have a corresponding branch instruction to test it.
– Pointy
Sep 6 '12 at 12:32
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What does !! mean in ruby?
... thing that is it used for legitimately is preventing a huge chunk of data from being returned. For example you probably don't want to return 3MB of image data in your has_image? method, or you may not want to return your entire user object in the logged_in? method. Using !! converts these objects...
Creating a “logical exclusive or” operator in Java
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Java does have a logical XOR operator, it is ^ (as in a ^ b).
Apart from that, you can't define new operators in Java.
Edit: Here's an example:
public static void main(String[] args) {
boolean[] all = { false, true };
for (boolean a : all) {
for (boolean b: all) {
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Hibernate Annotations - Which is better, field or property access?
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There are arguments for both, but most of them stem from certain user requirements "what if you need to add logic for", or "xxxx breaks encapsulation". However, nobody has really commented on the theory, and given a properly reasoned argument.
What is Hibernate/JPA actually ...
How do I loop through a list by twos? [duplicate]
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If you're using Python 2.6 or newer you can use the grouper recipe from the itertools module:
from itertools import izip_longest
def grouper(n, iterable, fillvalue=None):
"grouper(3, 'ABCDEFG', 'x') --> ABC DEF Gxx"
args = [iter(iterable)] * n
return izip_longest(fillvalue=f...
Why does a base64 encoded string have an = sign at the end
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From Wikipedia:
The final '==' sequence indicates that the last group contained only one byte, and '=' indicates that it contained two bytes.
Thus, this is some sort of padding.
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How do I make my GUI behave well when Windows font scaling is greater than 100%
...file was last saved.
const
SmallFontsPixelsPerInch = 96;
function ScaleFromSmallFontsDimension(const X: Integer): Integer;
begin
Result := MulDiv(X, Screen.PixelsPerInch, SmallFontsPixelsPerInch);
end;
So, continuing the theme, another thing to be wary of is that if your project is developed...
How do I typedef a function pointer with the C++11 using syntax?
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It has a similar syntax, except you remove the identifier from the pointer:
using FunctionPtr = void (*)();
Here is an Example
If you want to "take away the uglyness", try what Xeo suggested:
#include <type_traits>
using FunctionPtr = std::add_pointer<void()>::type...
Get free disk space
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Working code snippet using GetDiskFreeSpaceEx from link by RichardOD.
// Pinvoke for API function
[DllImport("kernel32.dll", SetLastError = true, CharSet = CharSet.Auto)]
[return: MarshalAs(UnmanagedType.Bool)]
public static extern bool GetDiskFreeSpaceEx(string lpDirec...