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How do I shuffle an array in Swift?
...Distance` in < Swift 4.1
let d: Int = numericCast(arc4random_uniform(numericCast(unshuffledCount)))
let i = index(firstUnshuffled, offsetBy: d)
swapAt(firstUnshuffled, i)
}
}
}
extension Sequence {
/// Returns an array with the contents of this...
Sorting list based on values from another list?
...
Shortest Code
[x for _,x in sorted(zip(Y,X))]
Example:
X = ["a", "b", "c", "d", "e", "f", "g", "h", "i"]
Y = [ 0, 1, 1, 0, 1, 2, 2, 0, 1]
Z = [x for _,x in sorted(zip(Y,X))]
print(Z) # ["a", "d", "h", "b", "c", "e", "i", "f"...
Get item in the list in Scala?
...y(Array(1, 2, 3), Array(4, 5, 6))
// 1. paratheses
scala> a.map(_(0))
Array[String] = Array(1, 4)
// 2. apply
scala> a.map(_.apply(0))
Array[String] = Array(1, 4)
// 3. function literal
scala> a.map(a => a(0))
Array[String] = Array(1, 4)
// 4. lift
scala> a.m...
Most efficient way to create a zero filled JavaScript array?
...rray(5) you're creating an object that kinda looks like this: { length: 5, __proto__: Array.prototype } - try console.dir( Array(5) ). Notice that it doesn't have any properties 0, 1, 2, etc. But when you apply that unto the Array constructor, it's like saying Array(undefined, undefined, undefined, ...
Is there a command to refresh environment variables from the command prompt in Windows?
...
:SetFromReg
"%WinDir%\System32\Reg" QUERY "%~1" /v "%~2" > "%TEMP%\_envset.tmp" 2>NUL
for /f "usebackq skip=2 tokens=2,*" %%A IN ("%TEMP%\_envset.tmp") do (
echo/set %~3=%%B
)
goto :EOF
:: Get a list of environment variables from registry
:GetRegEnv
"%WinDir%\Syst...
What generates the “text file busy” message in Unix?
...tanding the underlying API to better see what is going on.
sleep.c
#define _XOPEN_SOURCE 700
#include <unistd.h>
int main(void) {
sleep(10000);
}
busy.c
#define _XOPEN_SOURCE 700
#include <assert.h>
#include <errno.h>
#include <stdio.h>
#include <sys/types.h>
#inc...
What should main() return in C and C++?
...
stdlib.h provides EXIT_SUCCESS and EXIT_FAILURE for this purpose
– Clay
Oct 15 '08 at 13:13
21
...
Remove ActiveRecord in Rails 3
...r config/application.rb doesn't have require 'rails/all' or require "active_record/railtie". Instead, for a standard Rails setup without ActiveRecord, it should have only the following requires:
require File.expand_path('../boot', __FILE__)
require "action_controller/railtie"
require "action_maile...
'id' is a bad variable name in Python
...() is a fundamental built-in:
Help on built-in function id in module
__builtin__:
id(...)
id(object) -> integer
Return the identity of an object. This is guaranteed to be unique among
simultaneously existing objects. (Hint: it's the object's memory
address.)
In g...
SQLite add Primary Key
...OB,
PRIMARY KEY (field2, field1)
);
Reference: http://www.sqlite.org/lang_createtable.html
This answer does not address table alteration.
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