Tutorial by Examples: s

You can define implementation for specific instantiations of a template class/method. For example if you have: template <typename T> T sqrt(T t) { /* Some generic implementation */ } You can then write: template<> int sqrt<int>(int i) { /* Highly optimized integer implement...

Sort an enumeration in either ascending or descending order Synonyms: Sort-Object sort Assuming: $names = @( "Aaron", "Aaron", "Bernie", "Charlie", "Danny" ) Ascending sort is the default: $names | Sort-Object $names | sort Aaron Aa...

Projecting an enumeration allows you to extract specific members of each object, to extract all the details, or to compute values for each object Synonyms: Select-Object select Selecting a subset of the properties: $dir = dir "C:\MyFolder" $dir | Select-Object Name, FullName, Att...

Class methods present alternate ways to build instances of classes. To illustrate, let's look at an example. Let's suppose we have a relatively simple Person class: class Person(object): def __init__(self, first_name, last_name, age): self.first_name = first_name self.last...

There are two types of using keyword usage, using statement and using directive: using statement: The using keyword ensures that objects that implement the IDisposable interface are properly disposed after usage. There is a separate topic for the using statement using directive The using...

raw_data = {'first_name': ['John', 'Jane', 'Jim'], 'last_name': ['Doe', 'Smith', 'Jones'], 'department': ['Accounting', 'Sales', 'Engineering'],} df = pd.DataFrame(raw_data,columns=raw_data.keys()) df.to_csv('data_file.csv')

class Car { public position: number = 0; private speed: number = 42; move() { this.position += this.speed; } } In this example, we declare a simple class Car. The class has three members: a private property speed, a public property position and a public met...

class Car { public position: number = 0; protected speed: number = 42; move() { this.position += this.speed; } } class SelfDrivingCar extends Car { move() { // start moving around :-) super.move(); super.move(); } } ...

In this example we use the constructor to declare a public property position and a protected property speed in the base class. These properties are called Parameter properties. They let us declare a constructor parameter and a member in one place. One of the best things in TypeScript, is automatic ...

public class Singleton { private static final Singleton INSTANCE = new Singleton(); private Singleton() {} public static Singleton getInstance() { return INSTANCE; } } It can be argued that this example is effectively lazy initialization. Section 12.4.1 of ...

To implement an item click listener and/or an item long click listener, you can create an interface in your adapter: public class CustomAdapter extends RecyclerView.Adapter<CustomAdapter.ViewHolder> { public interface OnItemClickListener { void onItemSeleted(int position, Vi...

countMatches method from org.apache.commons.lang3.StringUtils is typically used to count occurences of a substring or character in a String: import org.apache.commons.lang3.StringUtils; String text = "One fish, two fish, red fish, blue fish"; // count occurrences of a substring Str...

Method references allow predefined static or instance methods that adhere to a compatible functional interface to be passed as arguments instead of an anonymous lambda expression. Assume that we have a model: class Person { private final String name; private final String surname; ...

Start with an iterable which needs to be grouped lst = [("a", 5, 6), ("b", 2, 4), ("a", 2, 5), ("c", 2, 6)] Generate the grouped generator, grouping by the second element in each tuple: def testGroupBy(lst): groups = itertools.groupby(lst, key=lambda...

Scalars are Perl's most basic data type. They're marked with the sigil $ and hold a single value of one of three types: a number (3, 42, 3.141, etc.) a string ('hi', "abc", etc.) a reference to a variable (see other examples). my $integer = 3; # number my $str...

Arrays store an ordered sequence of values. You can access the contents by index, or iterate over them. The values will stay in the order you filled them in. my @numbers_to_ten = (1,2,3,4,5,6,7,8,9,10); # More conveniently: (1..10) my @chars_of_hello = ('h','e','l','l','o'); my @word_list = ('Hel...

Hashes can be understood as lookup-tables. You can access its contents by specifiying a key for each of them. Keys must be strings. If they're not, they will be converted to strings. If you give the hash simply a known key, it will serve you its value. # Elements are in (key, value, key, value) se...

HTML <p>My shadow always follows me.</p> CSS p { -webkit-filter: drop-shadow(10px 10px 1px green); filter: drop-shadow(10px 10px 1px green); } Result

To use multiple filters, separate each value with a space. HTML <img src='donald-duck.png' alt='Donald Duck' title='Donald Duck' /> CSS img { -webkit-filter: brightness(200%) grayscale(100%) sepia(100%) invert(100%); filter: brightness(200%) grayscale(100%) sepia(100%) invert(1...

A Bootstrap carousel is a Bootstrap component that creates a slideshow which cycles through elements within the carousel. Here is a basic HTML usage example: <div id="carousel-example-generic" class="carousel slide" data-ride="carousel"> <!-- Indicators --...