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What columns generally make good indexes?
... you are required to search particular records. Suppose, we have a table named buyers where the SELECT query uses indexes like below:
SELECT
buyer_id /* no need to index */
FROM buyers
WHERE first_name='Tariq' /* consider to use index */
AND last_name='Iqbal' /* consider to use index */
Since ...
Analyze audio using Fast Fourier Transform
...rom 0 in multiples of 172 Hz until you get to 128. In an FFT, you only can measure frequencies up to half your sample points. Read these links on the Nyquist Frequency and Nyquist-Shannon Sampling Theorem if you are a glutton for punishment and need to know why, but the basic result is that your low...
Default value of a type at Runtime [duplicate]
...
I posted the same solution but I was unsure about how nullables were treated. It turns out nullables fall into the first branch but Activator.CreateInstance(typeof(int?)) actually returns null so it all works out.
– Jo...
PHP $_SERVER['HTTP_HOST'] vs. $_SERVER['SERVER_NAME'], am I understanding the man pages correctly?
...t’s a little bit more difficult. See Chris Shiflett’s article SERVER_NAME Versus HTTP_HOST.
It seems that there is no silver bullet. Only when you force Apache to use the canonical name you will always get the right server name with SERVER_NAME.
So you either go with that or you check the host...
Java - No enclosing instance of type Foo is accessible
...articular instance of Hello (even if it never uses or refers to it), which means it's an error to say new Thing(); without having a particular Hello instance in scope.
If you declare it as a static class instead, then it's a "nested" class, which doesn't need a particular Hello instance.
...
Protecting executable from reverse engineering?
...ncrease the likelihood that J Random Cracker will wander off and work on something easier instead.
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What are the differences between .so and .dylib on osx?
...ylib is the dynamic library extension on OSX, but it's never been clear to me when I can't / shouldn't use a traditional unix .so shared object.
...
Generate all permutations of a list without adjacent equal elements
... the remaining item types unless it was just taken. (See also Coady's implementation of this algorithm.)
import collections
import heapq
class Sentinel:
pass
def david_eisenstat(lst):
counts = collections.Counter(lst)
heap = [(-count, key) for key, count in counts.items()]
heapq...
What is the meaning of “POSIX”?
What is POSIX? I have read the Wikipedia article and I read it every time I encounter the term. The fact is that I never really understood what it is.
...
Hook up Raspberry Pi via Ethernet to laptop without router? [closed]
... and it works like a charm.
Material
a cross-over Ethernet cable (the name is fancy but it's just a normal Ethernet cable)
a laptop (ubuntu)
a Raspberry Pi (I have the Pi2)
Prerequisites on your ubuntu
Install network-manager
$sudo apt-get install network-manager
Install nmap
$sudo apt-ge...