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What is null in Java?
...ceof operator is true if the value of the RelationalExpression is not null and the reference could be cast to the ReferenceType without raising a ClassCastException. Otherwise the result is false.
This means that for any type E and R, for any E o, where o == null, o instanceof R is always false.
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How to convert SSH keypairs generated using PuTTYgen (Windows) into key-pairs used by ssh-agent and
I've generated key pairs using PuTTYgen and been logging in using Pageant, so that I have to enter my pass-phrase only once when my system boots.
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Why does running the Flask dev server run itself twice?
I'm using Flask for developing a website and while in development I run flask using the following file:
6 Answers
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How to implement common bash idioms in Python? [closed]
...y textfile manipulation through a bunch of badly remembered AWK, sed, Bash and a tiny bit of Perl.
17 Answers
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How to inspect Javascript Objects
...for inspection, unless you use a "spy"; basically, you override the object and write some code which does a for-in loop inside the object's context.
For in looks like:
for (var property in object) loop();
Some sample code:
function xinspect(o,i){
if(typeof i=='undefined')i='';
if(i.leng...
Picking a random element from a set
How do I pick a random element from a set?
I'm particularly interested in picking a random element from a
HashSet or a LinkedHashSet, in Java.
Solutions for other languages are also welcome.
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How do you know a variable type in java?
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@Miguel: since the only way you can handle an int value is in an int variable, there's no way to write code that handles a int value and doesn't know that type. The matter is different in case you're handling a wrapper like Integer, but then the code of this ans...
Is it better to use std::memcpy() or std::copy() in terms to performance?
...ll have a slight, almost imperceptible performance loss. I just did a test and found that to be untrue: I did notice a performance difference. However, the winner was std::copy.
I wrote a C++ SHA-2 implementation. In my test, I hash 5 strings using all four SHA-2 versions (224, 256, 384, 512), and ...
Fast permutation -> number -> permutation mapping algorithms
...you have n possibilities, so you can describe this with a number between 0 and n-1. For the position that the next element ends up at, you have n-1 remaining possibilities, so you can describe this with a number between 0 and n-2.
Et cetera until you have n numbers.
As an example for n = 5, consid...
Which is more efficient, a for-each loop, or an iterator?
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If you are just wandering over the collection to read all of the values, then there is no difference between using an iterator or the new for loop syntax, as the new syntax just uses the iterator underwater.
If however, you mean by loop the ...