What does 2 colons mean?

Two colons are used for an Error guard (one or more error numbers). Colon + space are used in class definitions to indicate inheritance.

What is colon in Scala?

First thing is that, in the strict sense, Scala does not have operators. It only has methods defined on objects. And when a Symbol (that is, a method name) ends with a colon, it means it is actually defined on the right operand, instead of it being a method on the left operand. For example “operator_:”.

Why do people use double colons?

Use the double colon operator (::) to qualify a C++ member function, a top level function, or a variable with global scope with: An overloaded name (same name used with different argument types) An ambiguous name (same name used in different classes)

What does colon mean in a for loop?

else
The colon here means “else”. 2: In a for-each loop: double[] vals = new double[100]; //fill x with values for (double x : vals) { //do something with x }

What does double colon mean PHP?

Scope Resolution Operator
In PHP, the double colon :: is defined as Scope Resolution Operator. It used when when we want to access constants, properties and methods defined at class level. When referring to these items outside class definition, name of class is used along with scope resolution operator.

What does double colon mean in Python?

The double colons (::) in python are used for jumping of elements in multiple axes. It is also a slice operator. Every item of the sequence gets sliced using double colon. The syntax of a Slice operator using double colon is [Start : Stop : Steps].

What does ++ mean in Scala?

++= can mean two different things in Scala: 1: Invoke the ++= method. In your example with flatMap , the ++= method of Builder takes another collection and adds its elements into the builder. Many of the other mutable collections in the Scala collections library define a similiar ++= method.

What is Scala collection immutable Colon Colon?

scala.collection.immutable.$colon$colon refers to scala’s :: which is actually the type of a non-empty List. If you are new to scala (or programming in Java) I suggest you had a look at List it’s two subclasses: Nil (the empty list) and ::` (the non-empty list).

What does double colon mean Python?

What is the difference between single colon and double colon in Python?

No, there is no difference. The start and step arguments default to None. Slice objects have read-only data attributes start, stop and step which merely return the argument values (or their default).

What does double colon mean in python?

What is the double colon in Java?

The double colon (::) operator, also known as method reference operator in Java, is used to call a method by referring to it with the help of its class directly. The only difference it has from lambda expressions is that this uses direct reference to the method by name instead of providing a delegate to the method.