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What's the best way to build a string of delimited items in Java?
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I am wondering - does this take into account if the String representation of an Object in the Collection contains the delimiter character itself?
– GreenieMeanie
Jul 8 '09 at 20:03
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Array to Hash Ruby
...e comments): "Be very careful with this. Ruby expands splats on the stack. If you do this with a large dataset, expect to blow out your stack."
So, for most general use cases this method is great, but use a different method if you want to do the conversion on lots of data. For example, @Łukasz Nie...
How to perform Callbacks in Objective-C
...ss" and MyClass calls the delegate methods on the delegate as appropriate. If your delegate callbacks are optional, you'll typically guard them at the dispatch site with something like "if ([delegate respondsToSelector:@selector(myClassWillDoSomething:)) {". In my example, the delegate is required t...
How do I use su to execute the rest of the bash script as that user?
...roject. The script is supposed to switch (su) to the username, cd to a specific directory based upon the project string.
9 ...
Where'd padding go, when setting background Drawable?
... patch as a background resource reset the padding - although interestingly if I added a color, or non-9 patch image, it didn't. The solution was to save the padding values before the background gets added, then set them again afterwards.
private EditText value = (EditText) findViewById(R.id.value)...
pandas DataFrame: replace nan values with average of columns
...ld be a scalar or a dict, however, it seems to work with a Series as well. If you want to pass a dict, you could use df.mean().to_dict().
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How do I get the parent directory in Python?
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@tzot: unfortunately os.path.dirname gives different results depending on whether a trailing slash is included in the path. If you want reliable results you need to use the os.path.join method in answer above.
– Artfunkel
Jun 28 '...
How do I select an entire row which has the largest ID in the table?
...ow
FROM table
WHERE id=(
SELECT max(id) FROM table
)
Note that if the value of max(id) is not unique, multiple rows are returned.
If you only want one such row, use @MichaelMior's answer,
SELECT row from table ORDER BY id DESC LIMIT 1
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C++ Lock-free Hazard Pointer（冒险指针） - C/C++ - 清泛网 - 专注C/C++及内核技术
...ount *Ref() {
++cnt_;
return this;
}
void Deref() {
if (--cnt_ == 0) {
delete this;
}
}
private:
std::unique_ptr<T> ptr_;
std::atomic_uint32_t cnt_;
};
仔细观察可以发现：
每一次的读取操作对应引用计数中增加的数值 1；
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How do I check OS with a preprocessor directive?
I need my code to do different things based on the operating system on which it gets compiled. I'm looking for something like this:
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