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What is DOCTYPE?
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Basically, the DOCTYPE describes the HTML that will be used in your page.
Browsers also use the DOCTYPE to determine how to render a page. Not including a DOCTYPE or including an incorrect one can trigger quirks mode.
The kicker...
What is the difference between null and undefined in JavaScript?
...he typeof operator returns 'object' for a value that is null. This was actually an error in the original JavaScript implementation that was then copied in ECMAScript. Today, it is rationalized that null is considered a placeholder for an object, even though, technically, it is a primitive value."
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How to tell where a header file is included from?
How can I tell where g++ was able to find an include file? Basically if I
4 Answers
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R - Concatenate two dataframes?
...2 data frames, you can use Reduce(rbind, list_of_data_frames) to mash them all together!
– Yourpalal
Aug 13 '15 at 21:12
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What is the best practice for dealing with passwords in git repositories?
...he password info from a configuration file. If your configuration file is called foobar.config, then you would commit a file called foobar.config.example to the repository, containing sample data. To run your program, you would create a local (not tracked) file called foobar.config with your real pa...
Big O of JavaScript arrays
...pending - Amortized O(1) (sometimes resizing the hashtable is required; usually only insertion is required)
Prepending - O(n) via unshift, since it requires reassigning all the indexes
Insertion - Amortized O(1) if the value does not exist. O(n) if you want to shift existing values (Eg, using splice...
Why is it bad practice to call System.gc()?
...ring a 1.5GB HashMap) with System.gc() , I was told it's bad practice to call System.gc() manually, but the comments were not entirely convincing. In addition, no one seemed to dare to upvote, nor downvote my answer.
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Redirect stderr and stdout in Bash
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@Daniel, but this question is specifically about bash
– John La Rooy
Aug 19 '13 at 3:38
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Big-oh vs big-theta [duplicate]
It seems to me like when people talk about algorithm complexity informally, they talk about big-oh. But in formal situations, I often see big-theta with the occasional big-oh thrown in.
I know mathematically what the difference is between the two, but in English, in what situation would using big-oh...
How to use Class in Java?
There's a good discussion of Generics and what they really do behind the scenes over at this question , so we all know that Vector<int[]> is a vector of integer arrays, and HashTable<String, Person> is a table of whose keys are strings and values Person s.
However, what stumps me ...