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Looking for a clear definition of what a “tokenizer”, “parser” and...
...hes extra context to the tokens -- this token is a number, that token is a string literal, this other token is an equality operator.
A parser takes the stream of tokens from the lexer and turns it into an abstract syntax tree representing the (usually) program represented by the original text.
Las...
How do MySQL indexes work?
...lision number is high cause you'll only perform the second comparison (the string one) against the repeated hashes.
Unfortunately, using this technique, you still need to hit the table to compare the url field.
Wrap up
Some facts that you may consider every time you want to talk about optimizatio...
Best way to determine user's locale within browser
...er and spits it back out as a JavaScript file with the header value in the string, eg.:
var acceptLanguage= 'en-gb,en;q=0.7,de;q=0.3';
then you could include a <script src> pointing at that external service in the HTML, and use JavaScript to parse the language header. I don't know of any ex...
Remove elements from collection while iterating
...
Old Timer Favorite (it still works):
List<String> list;
for(int i = list.size() - 1; i >= 0; --i)
{
if(list.get(i).contains("bad"))
{
list.remove(i);
}
}
Benefits:
It only iterates over the list once
No extra objects ...
Are loops really faster in reverse?
...
i-- is as fast as i++
This code below is as fast as yours, but uses an extra variable:
var up = Things.length;
for (var i = 0; i < up; i++) {
Things[i]
};
The recommendation is to NOT evaluate the size of the array each time. For big arrays one can see the performance degradation.
...
Get MIME type from filename extension
...ing.GetMimeMapping method, that is part of the BCL in .NET Framework 4.5:
string mimeType = MimeMapping.GetMimeMapping(fileName);
If you need to add custom mappings you probably can use reflection to add mappings to the BCL MimeMapping class, it uses a custom dictionary that exposes this method, ...
Centering a div block without the width
...S rule. This is a good trick to center a div in a container without adding extra HTML nor applying constraining styles to the container (like text-align: center; which would center all other inline content in the container), while keeping dynamic width for the contained div:
HTML:
<div class="c...
Virtual functions and performance - C++
...an instruction cache miss like a non-virtual function.
In many cases, two extra cache misses are not a concern, but in a tight loop on performance critical code it can dramatically reduce performance.
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Set cookie and get cookie with JavaScript [duplicate]
...Time() + (days*24*60*60*1000));
expires = "; expires=" + date.toUTCString();
}
document.cookie = name + "=" + (value || "") + expires + "; path=/";
}
function getCookie(name) {
var nameEQ = name + "=";
var ca = document.cookie.split(';');
for(var i=0;i < ca.length;i++...
What is a Java ClassLoader?
...ollowing simple class:
public class HelloApp {
public static void main(String argv[]) {
System.out.println("Aloha! Hello and Bye");
}
}
If you run this class specifying the -verbose:class command-line option, so that it prints what classes are being loaded, you will get an output that...