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Why is “using namespace std;” considered bad practice?
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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...
What is a Context Free Grammar?
...y and then the Wikipedia entry on formal grammar, I am left utterly and totally befuddled. Would someone be so kind as to explain what these things are?
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How to understand nil vs. empty vs. blank in Ruby
...s the negation of .blank?.
Array gotcha: blank? will return false even if all elements of an array are blank. To determine blankness in this case, use all? with blank?, for example:
[ nil, '' ].blank? == false
[ nil, '' ].all? &:blank? == true
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Get elements by attribute when querySelectorAll is not available without using libraries?
... and returns only those elements with a "data-foo" attribute:
function getAllElementsWithAttribute(attribute)
{
var matchingElements = [];
var allElements = document.getElementsByTagName('*');
for (var i = 0, n = allElements.length; i < n; i++)
{
if (allElements[i].getAttribute(attri...
Do c++11 lambdas capture variables they don't use?
When I use [=] to indicate that I would like all local variables to be captured by value in a lambda, will that result in all local variables in the function being copied, or just all local variables that are used by the lambda ?
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Search code inside a Github project
...e when using the default search selector "Everything":)
(I suppose we can all than Tim Pease, which had in one of his objectives "hacking on improved search experiences for all GitHub properties", and I did mention this Stack Overflow question at the time ;) )
Here is an illustration of a grep wit...
Limit file format when using ?
...tioned here, but is not the default in the dropdown. The default filter is All files (*).]
You can also use asterisks in MIME-types. For example:
<input type="file" accept="image/*" /> <!-- all image types -->
<input type="file" accept="audio/*" /> <!-- all audio types --&g...
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)
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Writing data into CSV file in C#
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UPDATE
Back in my naïve days, I suggested doing this manually (it was a simple solution to a simple question), however due to this becoming more and more popular, I'd recommend using the library CsvHelper that does all the safety checks, etc.
CSV is way more complicated than wha...
How can I replace a newline (\n) using sed?
...ns not to do it on the last line as there should be one final newline).
Finally the substitution replaces every newline with a space on the pattern space (which is the whole file).
Here is cross-platform compatible syntax which works with BSD and OS X's sed (as per @Benjie comment):
sed -e ':a' -...