Tutorial by Examples: t

Implicit classes make it possible to add new methods to previously defined classes. The String class has no method withoutVowels. This can be added like so: object StringUtil { implicit class StringEnhancer(str: String) { def withoutVowels: String = str.replaceAll("[aeiou]", &quo...

Think about a situation where we need to callback a function with arguments. std::function used with std::bind gives a very powerful design construct as shown below. class A { public: std::function<void(int, const std::string&)> m_CbFunc = nullptr; void foo() { ...

Assumptions for this example: You have a class, foo.bar.Baz. You'd like to create a run configuration that runs the main method. It's in a module called fooBar. In your gradle file: idea { workspace.iws.withXml { provider -> // I'm not actually sure why this is necessar...

Detailed instructions on getting model-view-controller set up or installed.

Redirect any naked domain to www.[your_domain].tld: # Start Apache Rewriting engine RewriteEngine On # Make sure you're not already using www subdomain # and that the host string is not empty RewriteCond %{HTTP_HOST} !^$ RewriteCond %{HTTP_HOST} !^www\. # We check for http/https connection ...

insert :: Ord a => a -> [a] -> [a] insert x [] = [x] insert x (y:ys) | x < y = x:y:ys | otherwise = y:(insert x ys) isort :: Ord a => [a] -> [a] isort [] = [] isort (x:xs) = insert x (isort xs) Example use: > isort [5,4,3,2,1] Result: [1,2,3,4...

Ordered merging of two ordered lists Preserving the duplicates: merge :: Ord a => [a] -> [a] -> [a] merge xs [] = xs merge [] ys = ys merge (x:xs) (y:ys) | x <= y = x:merge xs (y:ys) | otherwise = y:merge (x:xs) ys Top-down version: msort :: Ord a => [...

qsort :: (Ord a) => [a] -> [a] qsort [] = [] qsort (x:xs) = qsort [a | a <- xs, a < x] ++ [x] ++ qsort [b | b <- xs, b >= x]

XML pre-defines five general entities that can be used without declaring them: & " ' < > They are associated with the names amp, quot, apos, lt and gt. <?xml version="1.0"?> <entities> & is an ampersand. " is a quote. ' is...

It is possible to define one's own general entities. The declaration occurs in the DTD subset, with a name and the associated replacement text. It can then be used in the document using the entity reference syntax &...;, either in text, or in attribute values. <?xml version="1.0"?...

This is the most basic version of a trait in Scala. trait Identifiable { def getIdentifier: String def printIndentification(): Unit = println(getIdentifier) } case class Puppy(id: String, name: String) extends Identifiable { def getIdentifier: String = s"$name has id $id" } ...

Bash indirection permits to get the value of a variable whose name is contained in another variable. Variables example: $ red="the color red" $ green="the color green" $ color=red $ echo "${!color}" the color red $ color=green $ echo "${!color}" the ...

${parameter:-word} If parameter is unset or null, the expansion of word is substituted. Otherwise, the value of parameter is substituted. $ unset var $ echo "${var:-XX}" # Parameter is unset -> expansion XX occurs XX $ var="" # Parameter is null ...

The semantics for this are similar to that of default value substitution, but instead of substituting a default value, it errors out with the provided error message. The forms are ${VARNAME?ERRMSG} and ${VARNAME:?ERRMSG}. The form with : will error our if the variable is unset or empty, whereas the ...

1. URLByDeletingPathExtension: If the receiver represents the root path, this property contains a copy of the original URL. If the URL has multiple path extensions, only the last one is removed. 2. URLByAppendingPathExtension: Returns a new URL made by appending a path extension to the original U...

The figure contains all the plot elements. The main way to create a figure in matplotlib is to use pyplot. import matplotlib.pyplot as plt fig = plt.figure() You can optionally supply a number, which you can use to access a previously-created figure. If a number is not supplied, the last-create...

To create a JAR containing all of its dependencies, it is possible to use the built-in descriptor format jar-with-dependencies. The following example configures an execution of the Assembly Plugin bound to the package phase, using this built-in descriptor and declaring a main class of com.example: ...

Shortest match: $ a='I am a string' $ echo "${a#*a}" m a string Longest match: $ echo "${a##*a}" string

Shortest match: $ a='I am a string' $ echo "${a%a*}" I am Longest match: $ echo "${a%%a*}" I

First match: $ a='I am a string' $ echo "${a/a/A}" I Am a string All matches: $ echo "${a//a/A}" I Am A string Match at the beginning: $ echo "${a/#I/y}" y am a string Match at the end: $ echo "${a/%g/N}" I am a strinN Replace a pattern wi...