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Check if value already exists within list of dictionaries?
...sing the above code can give you a KeyError. You can fix this by using get and providing a default value. If you don't provide a default value, None is returned.
if not any(d.get('main_color', default_value) == 'red' for d in a):
# does not exist
...
private final static attribute vs private final attribute
...ce a static variable without having ever created an instances of the type, and any code referring to the variable is referring to the exact same data. Compare this with an instance variable: in that case, there's one independent version of the variable per instance of the class. So for example:
Tes...
How should I copy Strings in Java?
...e safe. The latter, however, is less efficient (it creates an extra object and in some cases copies the character data).
With this in mind, the first version should be preferred.
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Factory pattern in C#: How to ensure an object instance can only be created by a factory class?
... method of a factory class. Let us say I have some "business object" class and I want to make sure any instance of this class will have a valid internal state. In order to achieve this I will need to perform some check before creating an object, probably in its constructor. This is all okay until I ...
How can you find out which process is listening on a port on Windows?
...mmendation for TCPView. It looks very useful!
-a Displays all connections and listening ports.
-b Displays the executable involved in creating each connection or listening port. In some cases well-known executables host multiple independent components, and in these cases the sequence of components...
AsyncTask threads never die
...s to fetch data in response to the user pressing a button. This works well and keeps the interface responsive while fetching the data, but when I checked out what was going on in the Eclipse debugger, I found out that every time a new AsyncTask was created (which is quite often, because they can o...
What do the following phrases mean in C++: zero-, default- and value-initialization?
...thing to realize is that 'value-initialization' is new with the C++ 2003 standard - it doesn't exist in the original 1998 standard (I think it might be the only difference that's more than a clarification). See Kirill V. Lyadvinsky's answer for the definitions straight from the standard.
See this ...
Are HTTP headers case-sensitive?
...aders":
Each header field consists of a name followed by a colon (":") and the field value. Field names are case-insensitive.
The updating RFC 7230 does not list any changes from RFC 2616 at this part.
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tinyxml XML解析库下载（tinyxml2.h 和 tinyxml2.cpp） - 源码下载 - 清泛...
... to use this software for any
purpose, including commercial applications, and to alter it and
redistribute it freely, subject to the following restrictions:
1. The origin of this software must not be misrepresented; you must
not claim that you wrote the original software. If you use this
soft...
How is pattern matching in Scala implemented at the bytecode level?
...
case Sum(l,r) // instance of check followed by fetching the two arguments and assigning to two variables l and r but see below about custom extractors
case "hello" // equality check
case _ : Foo // instance of check
case x => // assignment to a fresh variable
case _ => // do nothing, this is...