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Django in / not in query
...e(); Tbl2.objects.filter(id__in=IDs') This did not work because IDs is actually a QuerySet object. When I deleted the rows it originated from, it no longer worked with other queries. The solution is Tbl2.objects.filter(id__in=list(IDs)) -- turn it into a list
– Dakusan
...
Where does gcc look for C and C++ header files?
...stem header.
If you run gcc in verbose mode on such a source, it will list all the system include locations as it looks for the bogus header.
$ echo "#include <bogus.h>" > t.c; gcc -v t.c; rm t.c
[..]
#include "..." search starts here:
#include <...> search starts here:
/usr/local...
Equals(=) vs. LIKE
...tify an example where these operators produce obviously different results. Allow me to quote from the MySQL manual:
Per the SQL standard, LIKE performs matching on a per-character basis, thus it can produce results different from the = comparison operator:
mysql> SELECT 'ä' LIKE 'ae' COLLA...
How do I format a string using a dictionary in python-3.x?
...3). In many languages, it is known as splat operator. In JavaScript, it's called spread operator. In python, there is no particular name given to this operator.
– abhisekp
Apr 15 '17 at 12:01
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Create a tag in a GitHub repository
...m the official Linux Kernel Git documentation for git push:
--tags
All refs under refs/tags are pushed, in addition to refspecs explicitly listed on the command line.
Or if you just want to push a single tag:
git push origin <tag>
See also my answer to How do you push a tag to a r...
How to get the CPU Usage in C#?
I want to get the overall total CPU usage for an application in C#. I've found many ways to dig into the properties of processes, but I only want the CPU usage of the processes, and the total CPU like you get in the TaskManager.
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What is the copy-and-swap idiom?
...s arguably the most nuanced and difficult. How should it be done? What pitfalls need to be avoided?
The copy-and-swap idiom is the solution, and elegantly assists the assignment operator in achieving two things: avoiding code duplication, and providing a strong exception guarantee.
How does it wor...
How can I cast int to enum?
... (e.g. "2342342" -- assuming that's not a value of your enum), it will actually allow that without throwing an error! Your enum will have that value (2342342) even though it's not a valid choice in the enum itself.
– JoeCool
Jun 25 '13 at 15:14
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How would one write object-oriented code in C? [closed]
What are some ways to write object-oriented code in C? Especially with regard to polymorphism.
32 Answers
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How to find memory leak in a C++ code/project?
...e software tools
1
Understand the operator basics. The C++ operator new allocates heap memory. The delete operator frees heap memory. For every new, you should use a delete so that you free the same memory you allocated:
char* str = new char [30]; // Allocate 30 bytes to house a string.
delete ...