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The virtualenvwrapper utility simplifies working with virtual environments and is especially useful if you are dealing with many virtual environments/projects. Instead of having to deal with the virtual environment directories yourself, virtualenvwrapper manages them for you, by storing all virtual...

The OR (||) operator returns true if one of its two operands evaluates to true, otherwise it returns false. For example, the following code evaluates to true because at least one of the expressions either side of the OR operator is true: if (10 < 20) || (20 < 10) { print("Expression...

div { -webkit-transition: all 4s ease; -moz-transition: all 4s ease; -o-transition: all 4s ease; transition: all 4s ease; }

div { -webkit-transform: rotate(45deg); -moz-transform: rotate(45deg); -ms-transform: rotate(45deg); -o-transform: rotate(45deg); transform: rotate(45deg); }

The filter or map functions should often be replaced by list comprehensions. Guido Van Rossum describes this well in an open letter in 2005: filter(P, S) is almost always written clearer as [x for x in S if P(x)], and this has the huge advantage that the most common usages involve predicates tha...

The MATLAB Profiler is a tool for software profiling of MATLAB code. Using the Profiler, it is possible to obtain a visual representation of both execution time and memory consumption. Running the Profiler can be done in two ways: Clicking the "Run and Time" button in the MATLAB GUI...

Python 3.x3.3 Use yield from if you want to yield all values from another iterable: def foob(x): yield from range(x * 2) yield from range(2) list(foob(5)) # [0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 0, 1] This works with generators as well. def fibto(n): a, b = 1, 1 while True: ...

One might want to group their data by the runs of a variable and perform some sort of analysis. Consider the following simple dataset: (dat <- data.frame(x = c(1, 1, 2, 2, 2, 1), y = 1:6)) # x y # 1 1 1 # 2 1 2 # 3 2 3 # 4 2 4 # 5 2 5 # 6 1 6 The variable x has three runs: a run of l...

The module cmath includes additional functions to use complex numbers. import cmath This module can calculate the phase of a complex number, in radians: z = 2+3j # A complex number cmath.phase(z) # 0.982793723247329 It allows the conversion between the cartesian (rectangular) and polar repr...

To install Eclipse, go to the Eclipse Downloads Web page where there is usually a direct link to download the latest version of Eclipse. Starting Eclipse Mars (version 4.5), an installer can be downloaded which guides you through the installation procedure, as opposed to downloading the whole instal...

This a basic example aimed at new users. It does not focus on explaining the difference between char and cellstring. It might happen that you want to get rid of the ' in your strings, although you never added them. In fact, those are artifacts that the command window uses to distinguish between ...

Shift Use .shift to remove the first item of an array. For example: var array = [1, 2, 3, 4]; array.shift(); array results in: [2, 3, 4] Pop Further .pop is used to remove the last item from an array. For example: var array = [1, 2, 3]; array.pop(); array results in: [1, 2] Bot...

function Invoke-MyCmdlet { [CmdletBinding(SupportsShouldProcess = $true)] param() # ... }

class Person { [string] $FirstName [string] $LastName [string] Greeting() { return "Greetings, {0} {1}!" -f $this.FirstName, $this.LastName } } $x = [Person]::new() $x.FirstName = "Jane" $x.LastName = "Doe" $greeting = $x.Greeting() #...

Vector size is simply the number of elements in the vector: Current vector size is queried by size() member function. Convenience empty() function returns true if size is 0: vector<int> v = { 1, 2, 3 }; // size is 3 const vector<int>::size_type size = v.size(); cout << size...

Declaration-site variance can be thought of as declaration of use-site variance once and for all the use-sites. class Consumer<in T> { fun consume(t: T) { ... } } fun charSequencesConsumer() : Consumer<CharSequence>() = ... val stringConsumer : Consumer<String> = cha...

Use-site variance is similar to Java wildcards: Out-projection: val takeList : MutableList<out SomeType> = ... // Java: List<? extends SomeType> val takenValue : SomeType = takeList[0] // OK, since upper bound is SomeType takeList.add(takenValue) // Error, lower bound for...

MATLAB code can be saved in m-files to be reused. m-files have the .m extension which is automatically associated with MATLAB. An m-file can contain either a script or functions. Scripts Scripts are simply program files that execute a series of MATLAB commands in a predefined order. Scripts do no...

Reading a file line by line public class Main { public static void main(String[] args) { try { Scanner scanner = new Scanner(new File("example.txt")); while(scanner.hasNextLine()) { String line = scanner.nextLine(); ...

The data.table package provides a convenient way to group by runs in data. Consider the following example data: library(data.table) (DT <- data.table(x = c(1, 1, 2, 2, 2, 1), y = 1:6)) # x y # 1: 1 1 # 2: 1 2 # 3: 2 3 # 4: 2 4 # 5: 2 5 # 6: 1 6 The variable x has three runs: a run ...