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Why does `a == b or c or d` always evaluate to True?

...r is more literal minded. if name == "Kevin" or "Jon" or "Inbar": is logically equivalent to: if (name == "Kevin") or ("Jon") or ("Inbar"): Which, for user Bob, is equivalent to: if (False) or ("Jon") or ("Inbar"): The or operator chooses the first argument with a positive truth value: if ("Jon")...
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Align image in center and middle within div

...00%; height:100%"> <img src="http://www.garcard.com/images/garcard_symbol.png"> </div> JSFiddle share | improve this answer | follow ...
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Changes in import statement python3

...a single function. In Python 2 you were permitted to be semi-lazy: def sin_degrees(x): from math import * return sin(degrees(x)) Note that it already triggers a warning in Python 2: a.py:1: SyntaxWarning: import * only allowed at module level def sin_degrees(x): In modern Python 2 co...
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How do I shuffle an array in Swift?

...Distance` in < Swift 4.1 let d: Int = numericCast(arc4random_uniform(numericCast(unshuffledCount))) let i = index(firstUnshuffled, offsetBy: d) swapAt(firstUnshuffled, i) } } } extension Sequence { /// Returns an array with the contents of this...
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Mutex example / tutorial? [closed]

... The first person to catch the door-handle of the booth, is the one who is allowed to use the phone. He has to keep holding on to the handle of the door as long as he uses the phone, otherwise someone else will catch hold of the handle, throw him out and talk to his wife :) There's no queue system a...
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reference assignment is atomic so why is Interlocked.Exchange(ref Object, Object) needed?

In my multithreaded asmx web service I had a class field _allData of my own type SystemData which consists of few List<T> and Dictionary<T> marked as volatile . The system data ( _allData ) is refreshed once in a while and I do it by creating another object called newData and fill...
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How to draw a line in android

...rself just simple and clean add the line in xml. <View android:layout_width="match_parent" android:layout_height="1dp" android:background="@android:color/black" /> The example code I provided will generate a line that fills the screen in width and has a height of one dp. If you have ...
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Nullable Foreign Key bad practice?

... read. Only if you know better than Chris Date "what first normal form really means". If x and y are both nullable, and indeed in some row x and y are both null, then WHERE x=y does not yield true. This proves beyond reasonable doubt that null is not a value (because any real value is always equ...
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OceanBase使用libeasy原理源码分析:客户端 - 数据库(内核) - 清泛网 - 专...

...端》,作为客户端使用时,会涉及到一些数据结构,easy_session_t, easy_client_t, easy_hash_t, easy_hash_list_t等。 easy_session_t用来封装一个要发出去的请求,easy_client_t用来封装一个TCP连接的发起端,easy_hash_t是一个哈希表,easy_hash_list_t是...
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Can I list-initialize a vector of move-only type?

...nitializer list elements in the current revision of the language. Specifically, we have: typedef const E& reference; typedef const E& const_reference; typedef const E* iterator; typedef const E* const_iterator; const E* begin() const noexcept; // first element const E* end() const noexce...