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Unique fields that allow nulls in Django
...trings are equal to empty strings for uniqueness checks, under both Django and database rules.
You can force the admin interface to store NULL for an empty string by providing your own customized model form for Foo with a clean_bar method that turns the empty string into None:
class FooForm(forms....
Why would a static nested interface be used in Java?
... above example is redundant (a nested interface is automatically "static") and can be removed with no effect on semantics; I would recommend it be removed. The same goes for "public" on interface methods and "public final" on interface fields - the modifiers are redundant and just add clutter to the...
UnicodeDecodeError: 'charmap' codec can't decode byte X in position Y: character maps to
...coding. Which one you have to figure out yourself. Common ones are Latin-1 and UTF-8. Since 0x90 doesn't actually mean anything in Latin-1, UTF-8 (where 0x90 is a continuation byte) is more likely.
You specify the encoding when you open the file:
file = open(filename, encoding="utf8")
...
How to add extra namespaces to Razor pages instead of @using declaration?
... namespaces for views) Not Found
This has changed between MVC 3 Preview 1 and MVC 3 Beta (released just today). In Preview 1 Razor used the WebForms namespaces config section. However in the Beta there is a new config section that is seperate from the WebForms one. You will need to add the follwing...
Why should I prefer to use member initialization lists?
... this case, the constructor for B will call the default constructor for A, and then initialize a.x to 3. A better way would be for B's constructor to directly call A's constructor in the initializer list:
B()
: a(3)
{
}
This would only call A's A(int) constructor and not its default constructo...
Is it a good idea to use Google Guava library for Android development?
I am involved in the development of Android application which is a rather "thick" mobile client for a Web service. It heavily communicates with the server but also has a lot of inner logic too. So, I decided to use some features of Google Guava library to simplify development process. Here is a li...
Convert a number range to another range, maintaining ratio
...ed Jul 10 '12 at 2:11
Teddy GarlandTeddy Garland
11722 silver badges77 bronze badges
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Debug.Assert vs Exception Throwing
I've read plenty of articles (and a couple of other similar questions that were posted on StackOverflow) about how and when to use assertions, and I understood them well. But still, I don't understand what kind of motivation should drive me to use Debug.Assert instead of throwing a plain excep...
Is there a pattern for initializing objects created via a DI container
I am trying to get Unity to manage the creation of my objects and I want to have some initialization parameters that are not known until run-time:
...
Write to .txt file?
...this to the file";
fprintf(f, "Some text: %s\n", text);
/* print integers and floats */
int i = 1;
float py = 3.1415927;
fprintf(f, "Integer: %d, float: %f\n", i, py);
/* printing single chatacters */
char c = 'A';
fprintf(f, "A character: %c\n", c);
fclose(f);
...