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When saving, how can you check if a field has changed?
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Essentially, you want to override the __init__ method of models.Model so that you keep a copy of the original value. This makes it so that you don't have to do another DB lookup (which is always a good thing).
class Person(models.Model):
name = models.CharF...
How can I recall the argument of the previous bash command?
Is there a way in Bash to recall the argument of the previous command?
7 Answers
7
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snprintf and Visual Studio 2010
... the expected behavior for snprintf:
int snprintf( char* buffer, std::size_t buf_size, const char* format, ... );
Writes at most buf_size - 1 characters to a buffer. The resulting
character string will be terminated with a null character, unless
buf_size is zero. If buf_size is zero, nothi...
Collection that allows only unique items in .NET?
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If all you need is to ensure uniqueness of elements, then HashSet is what you need.
What do you mean when you say "just a set implementation"? A set is (by definition) a collection of unique elements that doesn't save element ...
Unable to execute dex: Multiple dex files define Lcom/myapp/R$array;
...ing the Java Build Path and seeing this new item, and unchecking the originally-included support library solved the problem for me.
– Tom Pace
Sep 26 '13 at 17:20
9
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Append text to input field
...might want to write a function:
//Append text to input element
function jQ_append(id_of_input, text){
var input_id = '#'+id_of_input;
$(input_id).val($(input_id).val() + text);
}
After you can just call it:
jQ_append('my_input_id', 'add this text');
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CoInitialize浅析一 - 操作系统(内核) - 清泛网 - 专注C/C++及内核技术
... push [ebp+8] ; pvReserved
769B2A2E call _CoInitializeEx@8 ; CoInitializeEx(x,x)
769B2A33 pop ebp
769B2A34 retn 4
可以看到，其中的实现还是比较简单的，它只是简单地调用了CoInitializeEx，将第二个...
Count how many records are in a CSV Python?
...aranteed to be a fixed size, so the only way to count them is to read them all.
– Martijn Pieters♦
Apr 19 '13 at 15:55
1
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What is a memory fence?
...ead/writes occur in the order you expect. For example a 'full fence' means all read/writes before the fence are comitted before those after the fence.
Note memory fences are a hardware concept. In higher level languages we are used to dealing with mutexes and semaphores - these may well be implemen...
How can you profile a Python script?
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Python includes a profiler called cProfile. It not only gives the total running time, but also times each function separately, and tells you how many times each function was called, making it easy to determine where you should make optimizations.
You c...