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Where are $_SESSION variables stored?
...ariable storage is determined by PHP's session.save_path configuration. Usually this is /tmp on a Linux/Unix system. Use the phpinfo() function to view your particular settings if not 100% sure by creating a file with this content in the DocumentRoot of your domain:
<?php
phpinfo();
?>
...
How are feature_importances in RandomForestClassifier determined?
...d in [1] (often cited, but unfortunately rarely read...). It is sometimes called "gini importance" or "mean decrease impurity" and is defined as the total decrease in node impurity (weighted by the probability of reaching that node (which is approximated by the proportion of samples reaching that no...
How do I check if there are duplicates in a flat list?
...
Use set() to remove duplicates if all values are hashable:
>>> your_list = ['one', 'two', 'one']
>>> len(your_list) != len(set(your_list))
True
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Get value from SimpleXMLElement Object
... i can't believe this is so complicated. why would they make a class called "getName" but not "getValue"? why would they print empty string if you printed it instead of converted it manually to (string). WHY??
– user151496
Oct 17 '16 at 12:31
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Resetting generator object in Python
I have a generator object returned by multiple yield. Preparation to call this generator is rather time-consuming operation. That is why I want to reuse the generator several times.
...
C++ Lock-free Hazard Pointer（冒险指针） - C/C++ - 清泛网 - 专注C/C++及内核技术
...s;
}
}
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；
当所有的读取操作都完成时引用计数归 0，此时内存可以安全回收。
总结起来，当...
How to know if an object has an attribute in Python
...n is that, if the property is likely to be there most of the time, simply call it and either let the exception propagate, or trap it with a try/except block. This will likely be faster than hasattr. If the property is likely to not be there most of the time, or you're not sure, using hasattr will pr...
How to limit the amount of concurrent async I/O operations?
... Stephen Toub, but the less announced news is that the async semaphore actually made it into the Beta release of .NET 4.5
If you look at our beloved SemaphoreSlim class (which you should be using since it's more performant than the original Semaphore), it now boasts the WaitAsync(...) series of ove...
Automatically add newline at end of curl response body
...or a curl request doesn't contain a trailing newline, I end up with this really annoying condition where the shell prompt is in the middle of the line, and escaping is messed up enough that when I put the last curl command on the screen, deleting characters from that curl command deletes the wrong c...
How can I alter a primary key constraint using SQL syntax?
...y constraint name, use query found here to look it up (or look up and drop all at once). http://stackoverflow.com/a/13948609/945875
– Justin
Dec 19 '13 at 20:06
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