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Why is “using namespace std;” considered bad practice?
...
This is not related to performance at all. But consider this: you are using two libraries called Foo and Bar:
using namespace foo;
using namespace bar;
Everything works fine, and you can call Blah() from Foo and Quux() from Bar without problems. But one day yo...
Why doesn't Dictionary have AddRange?
...doesn't have any meaning to an associative container, as the range of data allows for duplicate entries. E.g if you had an IEnumerable<KeyValuePair<K,T>> that collection does not guard against duplicate entries.
The behavior of adding a collection of key-value pairs, or even merging tw...
Difference between Activity Context and Application Context
...nformation about the current activity that is necessary to complete those calls. If you show the exact error message, might be able to point to what exactly it needs.
But in general, use the activity context unless you have a good reason not to.
...
Redis - Connect to Remote Server
I've just install Redis succesfully using the instructions on the Quick Start guide on http://redis.io/topics/quickstart on my Ubuntu 10.10 server. I'm running the service as dameon (so it can be run by init.d)
...
Emacs mode for Stack Overflow's markdown
I am using Org-mode in Emacs to handle all my technical documentation. I would like to use Emacs to prepare questions that I have for Stack Overflow. Is there an Emacs mode for that, or even better, an extension for Org-mode to handle Stack Overflow formatting? Ideally it should include all formatti...
Prefer composition over inheritance?
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Prefer composition over inheritance as it is more malleable / easy to modify later, but do not use a compose-always approach. With composition, it's easy to change behavior on the fly with Dependency Injection / Setters. Inheritance is more rigid as most languages do not allo...
Code block in numbered list (Wiki syntax)
...two
It is not perfect, because you end up with a more indent but it does allow one to use the wiki syntax for correctly formatted pre blocks over multiple lines.
As previously mentioned, the other proper way would be to use HTML mark up.
<ol>
<li>one</li>
<li>two</li&g...
SQL Server : Columns to Rows
...prior to applying the unpivot.
You could also use CROSS APPLY with UNION ALL to convert the columns:
select id, entityid,
indicatorname,
indicatorvalue
from yourtable
cross apply
(
select 'Indicator1', Indicator1 union all
select 'Indicator2', Indicator2 union all
select 'Indicator3', I...
Convert data.frame column format from character to factor
...e to the world of R.
mtcars #look at this built in data set
str(mtcars) #allows you to see the classes of the variables (all numeric)
#one approach it to index with the $ sign and the as.factor function
mtcars$am <- as.factor(mtcars$am)
#another approach
mtcars[, 'cyl'] <- as.factor(mtcars[...
In-Place Radix Sort
... general, but it should be fast.
Edit:
I got curious whether this code actually works, so I tested/debugged it while waiting for my own bioinformatics code to run. The version above now is actually tested and works. For 10 million sequences of 5 bases each, it's about 3x faster than an optimized i...