- What is enum in Swift?
- Can you extend an enum Swift?
- How do you declare an enum?
- When should I use enums?
- Is an enum a model?
- What is enum with example?
- How do you define an enum?
- Which is better #define or enum and why?
- What is the purpose of enums?
- What can you not do with enums?
- Are enums bad practice?
- Can enums be strings?
- What is the difference between enum and constant?
- How do you declare an enum in SQL?
- Is enum or constant better?
What is enum in Swift?
An enumeration defines a common type for a group of related values and enables you to work with those values in a type-safe way within your code.
Enumerations in Swift are first-class types in their own right.
Can you extend an enum Swift?
We can extend the enum in two orthogonal directions: we can add new methods (or computed properties), or we can add new cases. Adding new methods won’t break existing code. Adding a new case, however, will break any switch statement that doesn’t have a default case.
How do you declare an enum?
Declaration of enum in java :Enum declaration can be done outside a Class or inside a Class but not inside a Method. … First line inside enum should be list of constants and then other things like methods, variables and constructor.More items…•Dec 10, 2019
When should I use enums?
Enums are lists of constants. When you need a predefined list of values which do represent some kind of numeric or textual data, you should use an enum. You should always use enums when a variable (especially a method parameter) can only take one out of a small set of possible values.
Is an enum a model?
The definition I have for models is that they represent knowledge. With that logic, an enum should be a model. Moreover, I have seen in some codebases that enums are stored as tables in the DB so that the knowledge is stored in the DB itself and can be accessed later for joins, or from code.
What is enum with example?
An enum type is a special data type that enables for a variable to be a set of predefined constants. The variable must be equal to one of the values that have been predefined for it. Common examples include compass directions (values of NORTH, SOUTH, EAST, and WEST) and the days of the week.
How do you define an enum?
An enum is a special “class” that represents a group of constants (unchangeable variables, like final variables). To create an enum , use the enum keyword (instead of class or interface), and separate the constants with a comma.
Which is better #define or enum and why?
#define is a preprocessor command, enum is in the C or C++ language. It is always better to use enums over #define for this kind of cases. … Another one is that when you have a sequence of values you only have to give the beginning of the sequence in the enum, the other values get consecutive values.
What is the purpose of enums?
Enumerations offer an easy way to work with sets of related constants. An enumeration, or Enum , is a symbolic name for a set of values. Enumerations are treated as data types, and you can use them to create sets of constants for use with variables and properties.
What can you not do with enums?
Note. enums cannot extend any class. An enum cannot be a superclass. the order of appearance of enum constants is called their “natural order”, and defines the order used by other items as well: compareTo, iteration order of values, EnumSet, EnumSet.
Are enums bad practice?
It provides strong type safety. They have some disadvantages at times, but this is really typically related to situations where every possible option is not known in advance. If you have a fixed set of options, such as your example, then strong typed enums are a good thing, and should not be avoided.
Can enums be strings?
Note: you cannot set an enum to string as enums can only have integers. … However, it is possible to manipulate this default rule by specifying a value to elements in the set. In the C# enum example below, we used an initializer to assign a value to the elements.
What is the difference between enum and constant?
With a set of constants, any value of the same intrinsic type could be used, introducing errors. With an enum only the applicable values can be used. An Enum class is used to specify a range of constants that will be frequently used within an application.
How do you declare an enum in SQL?
An ENUM is a string object with a value chosen from a list of permitted values that are enumerated explicitly in the column specification at table creation time. See Section 11.3. 1, “String Data Type Syntax” for ENUM type syntax and length limits.
Is enum or constant better?
Enums limit you to the required set of inputs whereas even if you use constant strings you still can use other String not part of your logic. This helps you to not make a mistake, to enter something out of the domain, while entering data and also improves the program readability.