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Why is “if not someobj:” better than “if someobj == None:” in Python?
...a __nonzero__ special method (as do numeric built-ins, int and float), it calls this method. It must either return a bool value which is then directly used, or an int value that is considered False if equal to zero.
Otherwise, if the object has a __len__ special method (as do container built-ins, li...
What does the “yield” keyword do?
... list, you can read its items one by one. Reading its items one by one is called iteration:
>>> mylist = [1, 2, 3]
>>> for i in mylist:
... print(i)
1
2
3
mylist is an iterable. When you use a list comprehension, you create a list, and so an iterable:
>>> mylist = [...
Is it ever advantageous to use 'goto' in a language that supports loops and functions? If so, why?
...o this already):
Cleanly exiting a function
Often in a function, you may allocate resources and need to exit in multiple places. Programmers can simplify their code by putting the resource cleanup code at the end of the function, and all "exit points" of the function would goto the cleanup label....
How to find the size of localStorage
...ly developing a site that will make use of HTML5's localStorage. I've read all about the size limitations for different browsers. However, I haven't seen anything on how to find out the current size of a localStorage instance. This question seems to indicate that JavaScript doesn't have a built in...
How do I get the path and name of the file that is currently executing?
I have scripts calling other script files but I need to get the filepath of the file that is currently running within the process.
...
How to save all the variables in the current python session?
I want to save all the variables in my current python environment. It seems one option is to use the 'pickle' module. However, I don't want to do this for 2 reasons:
...
Accessing class variables from a list comprehension in the class definition
...ing a newly created local namespace and the original global namespace. (Usually, the suite contains only function definitions.) When the class’s suite finishes execution, its execution frame is discarded but its local namespace is saved. [4] A class object is then created using the inheritance lis...
Difference between Python's Generators and Iterators
...ry generator is an iterator, but not vice versa. A generator is built by calling a function that has one or more yield expressions (yield statements, in Python 2.5 and earlier), and is an object that meets the previous paragraph's definition of an iterator.
You may want to use a custom iterator, ra...
为何用了MoveWindow函数后窗口不显示 - C/C++ - 清泛网 - 专注C/C++及内核技术
...eate(IDD_xxx_DIALOG, this);dlg.MoveWindow(10, 10, 100, 100);调用对话框的MoveWindow函数后，对话框不显示？调...CxxxDlg dlg;dlg.Create(IDD_xxx_DIALOG, this);
dlg.MoveWindow(10, 10, 100, 100);
调用对话框的MoveWindow函数后，对话框不显示？调用ShowWindow(SW_SHOW)才...
OnInitDialog()中SetFocus()设置焦点不起作用解决方法 - VC/MFC - 清泛IT论...
...cus(m_wndEdit);   // 不起作用，请参照如下VS自动生成的注释。
    ...
    return TRUE; // 除非将焦点设置到控件，否则返回 TRUE
}
当然，改为return FALSE;能解决问题，但是感觉不太优雅，使用SendMessage解决，如...