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App Inventor 2 字典 vs 列表：同样存数据，性能差了10倍？ - App应用开发 ...
...<a href="https://www.fun123.cn/reference/blocks/dictionaries.html" target="_blank">https://www.fun123.cn/reference/blocks/dictionaries.html</a><br>- 列表积木文档：<a href="https://www.fun123.cn/reference/blocks/lists.html" target="_blank">https://www.fun123.cn/reference/blocks/lists.html</a><...
Virtual member call in a constructor
I'm getting a warning from ReSharper about a call to a virtual member from my objects constructor.
18 Answers
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How do I convert a pandas Series or index to a Numpy array? [duplicate]
... edited Nov 13 '19 at 21:13
Mr_and_Mrs_D
25.3k2929 gold badges149149 silver badges304304 bronze badges
answered Jun 21 '13 at 18:51
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Get list of a class' instance methods
...
You actually want TestClass.instance_methods, unless you're interested in what TestClass itself can do.
class TestClass
def method1
end
def method2
end
def method3
end
end
TestClass.methods.grep(/method1/) # => []
...
What does #defining WIN32_LEAN_AND_MEAN exclude exactly?
I found the explanation defining WIN32_LEAN_AND_MEAN "reduces the size of the Win32 header files by excluding some of the less frequently used APIs". Somewhere else I read that it speeds up the build process.
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How do I force Postgres to use a particular index?
...of why and what you can do instead can be found here. The reasons are basically that it's a performance hack that tends to cause more problems later down the line as your data changes, whereas PostgreSQL's optimizer can re-evaluate the plan based on the statistics. In other words, what might be a go...
Why does [5,6,8,7][1,2] = 8 in JavaScript?
...other array
That's why you get
[1,2,3] + [1,2] = 1,2,31,2
i.e.
var arr_1=[1,2,3];
var arr_2=[1,2];
arr_1 + arr_2; // i.e. 1,2,31,2
Basically in the first case it is used as index of array and in the second case it is itself an array.
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GitHub clone from pull request?
...sing the -b option and for pull request:
git clone https://github.com/user_name/repo_name.git -b feature/pull_request_name dir_name
In your case, the branch you want to clone is the source branch of the pull request (feature/mongoose-support):
git clone https://github.com/berstend/frappe.git -b ...
What's the idiomatic syntax for prepending to a short python list?
... @MattM. If you insert at the front of a list, python has to move all the other items one space forwards, lists can't "make space at the front". collections.deque (double ended queue) has support for "making space at the front" and is much faster in this case.
– fejfo
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C++ templates that accept only certain types
...ply forward-declare a global template, but only define (explicitly or partially specialise) it for the valid types:
template<typename T> class my_template; // Declare, but don't define
// int is a valid type
template<> class my_template<int> {
...
};
// All pointer types...