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How to count the number of set bits in a 32-bit integer?
...Hamming Weight', 'popcount' or 'sideways addition'.
The 'best' algorithm really depends on which CPU you are on and what your usage pattern is.
Some CPUs have a single built-in instruction to do it and others have parallel instructions which act on bit vectors. The parallel instructions (like x86's ...
MySQL ON vs USING?
... far as I can tell, USING() is just more convenient syntax, whereas ON allows a little more flexibility when the column names are not identical. However, that difference is so minor, you'd think they'd just do away with USING() .
...
Implementing INotifyPropertyChanged - does a better way exist?
...er with C# 5:
protected bool SetField<T>(ref T field, T value,
[CallerMemberName] string propertyName = null)
{...}
which can be called like this:
set { SetField(ref name, value); }
with which the compiler will add the "Name" automatically.
C# 6.0 makes the implementation easier:
protec...
How to remove non-alphanumeric characters?
I need to remove all characters from a string which aren't in a-z A-Z 0-9 set or are not spaces.
9 Answers
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Why does GCC generate such radically different assembly for nearly the same C code?
...e(). I'll spare you the assembly, but it is identical - register names and all.
Step 2: Mathematical reduction: x + (y ^ x) = y
sign can only take one of two values, 0 or 0x80000000.
When x = 0, then x + (y ^ x) = y then trivial holds.
Adding and xoring by 0x80000000 is the same. It flips the sign...
is it possible to change values of the array when doing foreach in javascript?
...
The callback is passed the element, the index, and the array itself.
arr.forEach(function(part, index, theArray) {
theArray[index] = "hello world";
});
edit — as noted in a comment, the .forEach() function can take a second...
Force CloudFront distribution/file update
...
Good news. Amazon finally added an Invalidation Feature. See the API Reference.
This is a sample request from the API Reference:
POST /2010-08-01/distribution/[distribution ID]/invalidation HTTP/1.0
Host: cloudfront.amazonaws.com
Authorization:...
Bamboo Vs. Hudson(a.k.a. Jenkins) vs Any other CI systems [closed]
...ur build process.
Deploy artifacts to servers (i.e. deploy the war if all the unit tests pass.)
Bamboo 2.7 supports Build Stages, which allow you to break up your build into a Unit Test Stage and a Deploy Stage. Only if the Unit Test Stage succeeds, the build will move on to the Deploy Stage....
When to use ' (or quote) in Lisp?
...al operator (quote) (or equivalent ' ) function does, yet this has been all over Lisp code that I've seen.
10 Answers
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When to add what indexes in a table in Rails
...
Should I add "index" to all the foreign keys like "xxx_id"?
It would be better, because it accelerates the search in sorting in this column. And Foreign keys are something searched for a lot.
Since Version 5 of rails the index will be created aut...