Introduction to Prolog list
- The prolog list is a function for collecting several values to operate on large-size data.
- The list is a data structure for grouping the entity to handle the application’s data.
- The list is a collection to store multiple data items using brackets.
- The list is a data structure to create groups of the different values using square brackets.
- The prolog list is functional to store various data items, and it differs by using comma symbols.
- The prolog list is used to insert, delete, update, and append operations of the large values.
- The list is a function to handle and operate different entities in similar or different categories.
Syntax
- The prolog list uses square brackets [prolog list] to store data.
- The data list differs by a comma after a single value.
- The list syntax is shown below.
- [Value1, Value2, Value3, …, Value ]
- Description
- The prolog list contains values of a similar category.
- The square bracket contains values and differentiates these values using commas.
- The prolog empty list syntax is shown below.
- [ ]
- Description
- The prolog list is either empty or non-empty.
- If the list is empty, then the bracket does not contain any value.
- The prolog list works with the head.
- [Head | value1, value2, value3]
- The list works with a tail.
- [Head| tail1, tail2, tail3]
- Description
- The vertical bar separates the head and tail of the list.
- The first value is called the head of the list.
- The other values except the first are called tail values.
- The list works with variables using the head.
[Head|_] = [Head| value1, value2, value].
- The list works with variables using a tail.
Tail = [value1, value2, value]
Prolist = [value| Tail].
- Description
- The prolog creates variables and contains lists with values.
- If this variable list is required in the main list, then include it in the head or tail part.
- Some prolog list syntaxes are given below.
[v1, v2 | [v3] ]
[v1, v2| [v3] ]
[v1, v2, v3| [ ] ]
How does the list work in Prolog?
Prolog comment works in the “pl” file
- Create a file with the “pl” extension.
Example: main. pl
- Create a list with list multiple entities.
Plist([Australia, india, japan, UK, USA]).
Prolog comment works in the console
- Open console or interpreter.
- Set the directory path of the “pl” file.
- Use the given prolog file.
[main].
- Use the list in the console.
Plist([Australia, india, japan, UK, USA]).
- Directly use the list in the prolog console.
[1, 2, 3, 4, 5] = [Australia, India, Japan, UK, USA].
Prolog comment works in the console.
- Method1: use with multiple variables.
[1, 2, 3, 4, 5] = [Australia, India, Japan, UK, USA].
- The “1” number is assigned for Australia.
Australia = 1
- The “2” number is assigned for India.
India = 2
- The “3” number is assigned for Japan.
Japan = 3
- The “4” number is Assigned for the Uk.
UK = 4
- The “5” number is assigned for the USA.
USA = 5
- Method2: use with a single variable.
A = [Australia, India, Japan, UK, USA].
Examples
Here are the following examples mentioned below
Example1: the basic list with a single variable example and output are below.
- Prolog console
| ?- A = [Australia, India, Japan, UK, USA].
Output
- Prolog console
| ?- C = [1, 2, 3, 4, 5, 6, 7].
Output
- Prolog console
| ?- D = [India, 1, USA, uk].
Output
- Description:
- The list contains a value in number, lowercase, and uppercase format.
- The list assigns a single variable and displays the same as a program.
Example2: the basic prolog list with multiple variables examples and output is below.
-
- Prolog console
[1, 2, 3, 4, 5] = [Australia, India, Japan, UK, USA].
Output
- Prolog console
[A, B, C, D, E] = [Australia, India, Japan, UK, USA].
Output
- Prolog console
[A, B, C, D, E] = [australia, india, japan, uk, usa].
Output
- Description:
- The list contains a value in number, lowercase, and uppercase format.
- The list assigns multiple variables and displays values with variables.
Example3: the list with tail example and the output shown below.
-
- Prolog console
| ?- Tail = [australia, india, japan, england, america],
C = [ countries | Tail].
Output
- Description:
- The prolog list specifies head and tail using a vertical bar.
- The other values except the first value are called a tail of the list.
Example4: the list with a head example with a single variable.
-
- Prolog console
| ?- [Head|_] = [australia, india, japan, england, america].
Output
- Description:
- The list specifies head and tail using a vertical bar.
- The first value is called the head of the list.
- Example5: the list with the required entity example and the output shows below.
- Prolog console
| ?- [_,Value|_] = [australia, india, japan, england, america].
Output
- Prolog console
| ?- [_,_,Value|_] = [australia, india, japan, england, america].
Output
- Prolog console
| ?- [_,_,_,Value|_] = [australia, india, japan, england, america].
Output
- Description:
- The list displays the required value using variable and underscores symbols.
- You specify the position of the value using a comma and underscore symbol.
Example6: the basic list example and the output shows below.
-
- pl file
cntry([australia, india, japan, england, america]).
- Prolog console
| ?- cntry(List).
Output
- Description:
- The file contains a list with the required value.
- You assign a list name with the required variable name.
- The output displays a list with the variable name.
- Prolog console
| ?- [Head|Tail] = [Countries, australia, india, japan, england, america].
Output
- Description:
- The list specifies head and tail using a vertical bar.
- The first value is called the head of the list.
- The other value is called the tail of the list.
Conclusion
- The list maintains a collection of the values in the applications.
- The prolog list operates on large size data of the database.
- The list creates applications that are user-friendly, fast, and lightweight.
- The list operates efficiently.
Recommended Articles
This is a guide to the Prolog list. Here we discuss How does the list work in Prolog along with the description and outputs. You may also have a look at the following articles to learn more –
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