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Designing function f(f(n)) == -n
...oof of why such a function can't exist, for all numbers, if it doesn't use extra information(except 32bits of int):
We must have f(0) = 0. (Proof: Suppose f(0) = x. Then f(x) = f(f(0)) = -0 = 0. Now, -x = f(f(x)) = f(0) = x, which means that x = 0.)
Further, for any x and y, suppose f(x) = y. We w...
How to get a string after a specific substring?
How can I get a string after a specific substring?
9 Answers
9
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Curly braces in string in PHP
What is the meaning of { } (curly braces) in string literals in PHP?
5 Answers
5
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How to call getClass() from a static method in Java?
...putStream when used in a MapReduce.
public static InputStream getResource(String resource) throws Exception {
ClassLoader cl = Thread.currentThread().getContextClassLoader();
InputStream is = cl.getResourceAsStream(resource);
return is;
}
...
how to detect search engine bots with php?
...
Check the $_SERVER['HTTP_USER_AGENT'] for some of the strings listed here:
http://www.useragentstring.com/pages/useragentstring.php
Or more specifically for crawlers:
http://www.useragentstring.com/pages/useragentstring.php?typ=Crawler
If you want to -say- log the number of ...
JSONP with ASP.NET Web API
..., and now I am trying to consume it using JQuery. I can get back the JSON string using Fiddler, and it seems to be ok, but because the service exists on a separate site, trying to call it with JQuery errors with the "Not Allowed". So, this is clearly a case where I need to use JSONP.
...
How to use enums in C++
...es themselves don't have members. What you wrote is the equivalent to std::string.clear. std::string is a type, so you can't use . on it. You use . on an instance of a class.
Unfortunately, enums are magical and so the analogy stops there. Because with a class, you can do std::string::clear to g...
Mutex example / tutorial? [closed]
... entry to the room much like the phone booth. So now, even though you have extra mutexes, you can reuse the phone booth in any project. Another option would be to expose locking mechanisms for each device in the room and manage the locks in the room class. Either way, you wouldn't add new locks to t...
What is the in a .vimrc file?
...der
To define a mapping which uses the "mapleader" variable, the special string
"<Leader>" can be used. It is replaced with the string value of "mapleader".
If "mapleader" is not set or empty, a backslash is used instead.
Example:
:map <Leader>A oanother line <Esc>
Works ...
BaseException.message deprecated in Python 2.6
...to the constructor. Suggested practice, though, is that only a
single string argument be passed to the constructor."""
__str__ and __repr__ are already implemented in a meaningful way,
especially for the case of only one arg (that can be used as message).
You do not need to repeat __str__ or _...