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Is Ruby pass by reference or by value?
... some simple pictures / explanations I wrote for him (apologies for the length and probably some oversimplification):
Q1: What happens when you assign a new variable str to a value of 'foo'?
str = 'foo'
str.object_id # => 2000
A: A label called str is created that points at the object 'fo...
boost::flat_map and its performance compared to map and unordered_map
... going to help calculate our PRECISION ERROR MARGIN
for (int i = 0; i < 80; ++i)
{
u64 tick1 = GetRDTSC();
u64 tick2 = GetRDTSC();
minDiff = std::min(minDiff, tick2 - tick1); // make many takes, take the smallest that ever come.
maxDiff = std::max(maxDiff...
Disable ALL CAPS menu items in Visual Studio 2013
...o 2013 Update 4)
As of Visual Studio 2013 Update 4 you can go into Tools > Options > Environment
and uncheck Turn off upper case in the menu bar
Before Visual Studio 2013 Update 4:
You need to create a specific registry key if you want "old-style" menus back.
First Variant: Since Pack...
Tests not running in Test Explorer
... check that the following 2 settings match:
[Right click test project] -> properties -> Build -> Platform target - e.g. x64
[Main Menu] -> Test -> Test Settings -> Default Processor Architecture -> X64
I found that when these didn't match my test project would silently fail ...
How to convert a string to lower or upper case in Ruby
...ngs. To convert to lowercase, use downcase:
"hello James!".downcase #=> "hello james!"
Similarly, upcase capitalizes every letter and capitalize capitalizes the first letter of the string but lowercases the rest:
"hello James!".upcase #=> "HELLO JAMES!"
"hello James!".capitalize #...
Remove all the elements that occur in one list from another
...
One way is to use sets:
>>> set([1,2,6,8]) - set([2,3,5,8])
set([1, 6])
Note, however, that sets do not preserve the order of elements, and cause any duplicated elements to be removed. The elements also need to be hashable. If these restric...
What does the “===” operator do in Ruby? [duplicate]
...uld b be a member of that set?"
For example:
(1..5) === 3 # => true
(1..5) === 6 # => false
Integer === 42 # => true
Integer === 'fourtytwo' # => false
/ell/ === 'Hello' # => true
/ell/ === 'Foobar' # => false
The main usage for the =...
How to replace a hash key with another key
...u can patch up the hash in place with this:
h.keys.each { |k| h[k[1, k.length - 1]] = h[k]; h.delete(k) }
The k[1, k.length - 1] bit grabs all of k except the first character. If you want a copy, then:
new_h = Hash[h.map { |k, v| [k[1, k.length - 1], v] }]
Or
new_h = h.inject({ }) { |x, (k,v)...
How do you divide each element in a list by an int?
...
>>> myList = [10,20,30,40,50,60,70,80,90]
>>> myInt = 10
>>> newList = map(lambda x: x/myInt, myList)
>>> newList
[1, 2, 3, 4, 5, 6, 7, 8, 9]
...
What's the difference between a continuation and a callback?
...array, callback) {
var length = array.length;
for (var i = 0; i < length; i++)
callback(array[i], array, i);
}
However if a function calls back another function as the last thing it does then the second function is called a continuation of the first. For example:
v...