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What does “hashable” mean in Python?
...ue which never changes during its lifetime (it needs a __hash__() method), and can be compared to other objects (it needs an __eq__() or __cmp__() method). Hashable objects which compare equal must have the same hash value.
Hashability makes an object usable as a dictionary key and a set member...
The written versions of the logical operators
This is the only place I've ever seen and , or and not listed as actual operators in C++. When I wrote up a test program in NetBeans, I got the red underlining as if there was a syntax error and figured the website was wrong, but it is NetBeans which is wrong because it compiled and ran as exp...
Internet Explorer 11 detection
...t && !!document.documentMode;
// true on IE11
// false on Edge and other IEs/browsers.
Original Answer
In order to check Ie11 , you can use this : ( tested)
(or run this)
!(window.ActiveXObject) && "ActiveXObject" in window
I have all VMS of IE :
Notice : this w...
How does a Java HashMap handle different objects with the same hash code?
As per my understanding I think:
14 Answers
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Node.js + Nginx - What now?
I've set up Node.js and Nginx on my server. Now I want to use it, but, before I start there are 2 questions:
12 Answers
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Using a dispatch_once singleton model in Swift
...tl;dr: Use the class constant approach if you are using Swift 1.2 or above and the nested struct approach if you need to support earlier versions.
From my experience with Swift there are three approaches to implement the Singleton pattern that support lazy initialization and thread safety.
Class c...
The JPA hashCode() / equals() dilemma
There have been some discussions here about JPA entities and which hashCode() / equals() implementation should be used for JPA entity classes. Most (if not all) of them depend on Hibernate, but I'd like to discuss them JPA-implementation-neutrally (I am using EclipseLink, by the way).
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What are the pros and cons of performing calculations in sql vs. in your application
...ed to access/aggregate a lot of data, doing it at the db server will save bandwidth, and disk io if the aggregates can be done inside indexes)
convenience (sql is not the best language for complex work - especially not great for procedural work, but very good for set-based work; lousy error-handling...
What is the difference between an int and an Integer in Java and C#?
...ut a particular type of programmer knowing the difference between an int and an Integer in Java/C# (Object-Oriented Programming Languages).
...
How is set() implemented?
...ython source code for set which, according to Achim Domma, is mostly a cut-and-paste from the dict implementation.
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