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What's the difference between returning void and returning a Task?
...arious C# Async CTP samples I see some async functions that return void , and others that return the non-generic Task . I can see why returning a Task<MyType> is useful to return data to the caller when the async operation completes, but the functions that I've seen that have a return typ...
Rename specific column(s) in pandas
...' else x for x in df.columns]
Or, construct a mapping using a dictionary and perform the list-comprehension with it's get operation by setting default value as the old name:
col_dict = {'gdp': 'log(gdp)', 'cap': 'cap_mod'} ## key→old name, value→new name
df.columns = [col_dict.get(x, x) fo...
How do you change Background for a Button MouseOver in WPF?
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@C-F the reason for this is the standard Button style has triggers inside ControlTemplate, so they override OP's Style triggers.
– torvin
Sep 22 '15 at 2:01
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Does Java casting introduce overhead? Why?
...t objects of one type to another? Or the compiler just resolves everything and there is no cost at run time?
5 Answers
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Good examples of Not a Functor/Functor/Applicative/Monad?
...ariant functor out of it, but not a (covariant) functor. Try writing fmap and you'll fail. Note that the contravariant functor version is reversed:
fmap :: Functor f => (a -> b) -> f a -> f b
contramap :: Contravariant f => (a -> b) -> f b -> f a
A type constr...
Django: “projects” vs “apps”
... ready to build using Django. I'm going to avoid using the terms "project" and "application" in this context, because I'm not clear on their specific meaning in Django.
...
Call method in directive controller from other controller
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This is an interesting question, and I started thinking about how I would implement something like this.
I came up with this (fiddle);
Basically, instead of trying to call a directive from a controller, I created a module to house all the popdown logic:
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StringUtils 字符串工具扩展：强大的文本处理工具集 · App Inventor 2 中文网
...返回扩展的版本号。
SDK版本 VersionSDK
返回当前运行的 Android API 级别。
方法 Methods
字符和大小写检测
获取字符 CharAt(索引)
返回指定位置的字符（1-based 索引）。
返回值：指...
Enable access control on simple HTTP server
...ever create a simple HTTP server yourself, using most of SimpleHTTPRequestHandler, and just add that desired header.
For that, simply create a file simple-cors-http-server.py (or whatever) and, depending on the Python version you are using, put one of the following codes inside.
Then you can do py...
How can I repeat a character in Bash?
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You can use:
printf '=%.0s' {1..100}
How this works:
Bash expands {1..100} so the command becomes:
printf '=%.0s' 1 2 3 4 ... 100
I've set printf's format to =%.0s which means that it will always print a single = no matter what argument it is given. Therefore it prints 100 =s.
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