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Can virtual functions have default parameters?
If I declare a base class (or interface class) and specify a default value for one or more of its parameters, do the derived classes have to specify the same defaults and if not, which defaults will manifest in the derived classes?
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Replacing NAs with latest non-NA value
In a data.frame (or data.table), I would like to "fill forward" NAs with the closest previous non-NA value. A simple example, using vectors (instead of a data.frame ) is the following:
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Any reason not to use '+' to concatenate two strings?
...hon is to concatenate a sequence of strings using + in a loop. This is bad because the Python interpreter has to create a new string object for each iteration, and it ends up taking quadratic time. (Recent versions of CPython can apparently optimize this in some cases, but other implementations ca...
How to draw a rounded Rectangle on HTML Canvas?
I found that there are only can fill rectangle, but no rounded corner one, how can I do that?
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Using Caps Lock as Esc in Mac OS X
How do I make Caps Lock work like Esc in Mac OS X?
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一文讲透区块链技术原理 - 资讯 - 清泛网 - 专注C/C++及内核技术
...据库技术，它基于密码学中的椭圆曲线数字签名算法（ECDSA）来实现去中心化的P2P系统设计。但区块链的作用不仅仅局限在比特币上。现在，人们在使用“区块链”这个词时，有的时候是指数据结构，有时是指数据库，有时则是...
Reflecting parameter name: abuse of C# lambda expressions or syntax brilliance?
I am looking at the MvcContrib Grid component and I'm fascinated, yet at the same time repulsed, by a syntactic trick used in the Grid syntax :
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How can I make a JPA OneToOne relation lazy
In this application we are developing, we noticed that a view was particularly slow. I profiled the view and noticed that there was one query executed by hibernate which took 10 seconds even if there only were two object in the database to fetch. All OneToMany and ManyToMany relations were lazy ...
Check whether user has a Chrome extension installed
I am in the process of building a Chrome extension, and for the whole thing to work the way I would like it to, I need an external JavaScript script to be able to detect if a user has my extension installed.
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git clone through ssh
I have a project on which I created a git repository:
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