大约有 15,000 项符合查询结果（耗时：0.0119秒） [XML]
Most efficient way to remove special characters from string
... @SILENT: No, it doesn't, but you should only do that once. If you allocate an array that large each time you call the method (and if you call the method frequently) then the method becomes the slowest by far, and causes a lot of work for the garbage collector.
– Guffa
...
Are global variables bad? [closed]
... higher performing code. "Passing" requires constant stack dynamic memory allocation, and this would be silly for something that ought to be a global, such as global buffer for incoming socket data. For example, if you have a function that reads Winsock recv(), why constantly create and deallocate...
How do I calculate tables size in Oracle
...
You might be interested in this query. It tells you how much space is allocated for each table taking into account the indexes and any LOBs on the table. Often you are interested to know "How much spaces the the Purchase Order table take, including any indexes" rather than just the table itsel...
What's the best way to communicate between view controllers?
...tionDidFinishLoading {
MyBookWarehouse *myWarehouse = [[MyBookWarehouse alloc]init];
MyCheckoutController *myCheckout = [[MyCheckoutController alloc]init];
BookPickerViewController *bookPicker = [[BookPickerViewController alloc]
initWithWarehouse:m...
Thou shalt not inherit from std::vector
...the absence of a virtual destructor is only a problem if the derived class allocates resources which must be freed upon destruction. (They wouldn't be freed in a polymorphic use case because a context unknowingly taking ownership of a derived object via pointer to base would only call the base dest...
Why would you ever implement finalize()?
...ction be taken prior to collection? That just puts us back in the days of malloc/free.)
Other times you need the resource you think you're managing to be more robust. For example, why do you need to close that connection? It must ultimately be based on some kind of I/O provided by the system (socke...
-didSelectRowAtIndexPath: not being called
...after I implemented UITapGestureRecognizer *tap = [[UITapGestureRecognizer alloc] initWithTarget:self action:@selector(dismissKeyboard)]; [self.view addGestureRecognizer:tap];
– coolcool1994
Jul 4 '13 at 21:31
...
Array initialization syntax when not in a declaration
... dynamic. Java wants to know at declaration time how much memory should be allocated for the array. An ArrayList is much more dynamic and the size of it can vary over time.
If you initialize your array with the length of two, and later on it turns out you need a length of three, you have to throw a...
What is the garbage collector in Java?
... loop. This means that in every iteration, a little bit of memory is being allocated to make a String object.
Going back to the code, we can see that once a single iteration is executed, in the next iteration, the String object that was created in the previous iteration is not being used anymore --...
What is the most efficient way to store tags in a database?
...ic items MUCH more simple. You don't have to create a new tag, remove the allocation of the old one and re-allocate a new one, you just edit the tagname.
For displaying a list of tags, you simply use DISTINCT or GROUP BY, and of course you can count how many times a tag is used easily, too.
...