What is a selector in Objective-C?

In Objective-C, selector has two meanings. It can be used to refer simply to the name of a method when it’s used in a source-code message to an object. It also, though, refers to the unique identifier that replaces the name when the source code is compiled. Compiled selectors are of type SEL .

What is a selector?

A selector is a chain of one or more simple selectors separated by combinators. Combinators are: white space, “>”, and “+”. White space may appear between a combinator and the simple selectors around it. The elements of the document tree that match a selector are called subjects of the selector.

What is a method selector?

A selector is an identifier which represents the name of a method. It is not related to any specific class or method, and can be used to describe a method of any class, whether it is a class or instance method. Simply, a selector is like a key in a dictionary.

What is a selector in HTML?

An HTML selector is the text portion of an HTML tag. For example, H3 is the selector for the tag . All HTML tags have default properties. The HTML selector can be used to control the behavior of its specific HTML tag.

What are selectors and what are their different types?

Simple selectors (select elements based on name, id, class) Combinator selectors (select elements based on a specific relationship between them) Pseudo-class selectors (select elements based on a certain state) Pseudo-elements selectors (select and style a part of an element)

What is Selector Swift?

Swift version: 5.4. Selectors are effectively the names of methods on an object or struct, and they are used to execute some code at runtime. They were common in Objective-C, but the earliest versions of Swift didn’t include some core selector functionality so their use declined for a while.

What is Selector and its types?

How do you write a selector?

When writing selectors, you should prioritize finding in this order:

  1. ID, name, class, or anything else that is unique to the element.
  2. Complex CSS selectors.
  3. XPath selectors.
  4. If none of the above work for you, then the last resort is to ask a developer to add a unique ID or class to the element you are trying to select.

Which type of selector is used in this case?

Discussion Forum

Que. What type of selector is used in this case? p {line- 150%;}
b. element Selectors
c. id Selectors
d. none of the mentioned
Answer:element Selectors

What is an element selector?

The element selector is a way to select all the elements with a given tag name in a document, and apply the same styles to each element with the tag name.

What is @objc function in Swift?

That’s where the @objc attribute comes in: when you apply it to a class or method it instructs Swift to make those things available to Objective-C as well as Swift code.

Categories: Common