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When is “i += x” different from “i = i + x” in Python?
...This depends entirely on the object i.
+= calls the __iadd__ method (if it exists -- falling back on __add__ if it doesn't exist) whereas + calls the __add__ method1 or the __radd__ method in a few cases2.
From an API perspective, __iadd__ is supposed to be used for modifying mutable objects i...
How to generate a Dockerfile from an image?
Is it possible to generate a Dockerfile from an image? I want to know for two reasons:
8 Answers
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What is the tilde (~) in the enum definition?
...
~ is the unary one's complement operator -- it flips the bits of its operand.
~0 = 0xFFFFFFFF = -1
in two's complement arithmetic, ~x == -x-1
the ~ operator can be found in pretty much any language that borrowed syntax from C, including Objective-C/C++/C#/Java/Java...
Convert object string to JSON
...SON.stringify(eval("(" + str + ")"));
Note that when you eval an object literal, it has to be wrapped in parentheses, otherwise the braces are parsed as a block instead of an object.
I also agree with the comments under the question that it would be much better to just encode the object in valid ...
C++11 introduced a standardized memory model. What does it mean? And how is it going to affect C++ p
...d a standardized memory model, but what exactly does that mean? And how is it going to affect C++ programming?
8 Answers
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How should I cast in VB.NET?
...o give you the string representation of an object, regardless of what type it is. Use this if var is not a string already.
CStr(var) is the VB string cast operator. I'm not a VB guy, so I would suggest avoiding it, but it's not really going to hurt anything. I think it is basically the same as CT...
How to break out of a loop from inside a switch?
I'm writing some code that looks like this:
19 Answers
19
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Making a property deserialize but not serialize with json.net
...e some configuration files which were generated by serializing C# objects with Json.net.
10 Answers
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What is lexical scope?
...n2()
{
printf("%d", x);
}
}
Every inner level can access its outer levels.
There is another way, called dynamic scope used by the first implementation of Lisp, again in a C-like syntax:
void fun()
{
printf("%d", x);
}
void dummy1()
{
int x = 5;
fun();
}
void dummy2...
warning about too many open figures
In a script where I create many figures with fix, ax = plt.subplots(...) , I get the warning RuntimeWarning: More than 20 figures have been opened. Figures created through the pyplot interface (matplotlib.pyplot.figure) are retained until explicitly closed and may consume too much memory.
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