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Prolog Operators
- Prolog - Type of Operators
- Prolog - Arithmetic Comparison Operators
- Prolog - Unification Operators
- Prolog - Term Comparision Operators
- Prolog - Arithmetic Operators
- Prolog - Logical Operators
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- Prolog - Custom Operators
Prolog Lists
- Prolog - Lists
- Prolog - Member of List
- Prolog - Length of List
- Prolog - Concatenating Lists
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- Prolog - Shift Items of a List
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- Prolog - SubSet of a Set
- Prolog - Union of Sets
- Prolog - Intersection of Sets
- Prolog - Even and Odd Length Finding
- Prolog - Divide a List
- Prolog - Find Maximum of a List
- Prolog - Find Minimum of a List
- Prolog - Find Sum of a List
- Prolog - Sorting List using MergeSort
Built-In Predicates
- Prolog - Built-In Predicates
- Prolog - Identifying Terms
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- Prolog - Collecting All
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Miscellaneous
- Recursion and Structures
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- Tree Data Structure (Case Study)
- Prolog - Examples
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- Prolog - Practical Arithmetic Examples
- Prolog - Examples of Cuts
- Towers of Hanoi Problem
- Prolog - Linked Lists
- Monkey and Banana Problem
- Prolog Useful Resources
- Prolog - Quick Guide
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- Prolog - Discussion
Prolog - Arithmetic Comparison Operators
Arithmetic Comparison operators are specifically used to compare numeric values of arithmetic states or expressions. Arithmetic expressions are evaluated before being compared using comparsion operators. Following is the list of arithmetic comparison operators −
| Operator | Meaning |
|---|---|
| X > Y | X is numerically greater than Y |
| X < Y | X is numerically less than Y |
| X >= Y | X is numerically greater than or equal to Y |
| X =< Y | X is numerically less than or equal to Y |
| X =:= Y | X and Y values are numerically equal |
| X =\= Y | X and Y values are not numerically equal |
You can see that the '=<' operator, '=:=' operator and '=\=' operators are syntactically different from other languages.
Example
GNU Prolog 1.5.0 (64 bits) Compiled Jul 8 2021, 12:33:56 with cl Copyright (C) 1999-2021 Daniel Diaz | ?- 1+2=:=2+1 . yes | ?- 1+2=2+1. no | ?- 1+A=B+2. A = 2 B = 1 yes | ?- 5<10. yes | ?- 5>10. no | ?- 10=\=100. yes | ?-
Here we can see 1+2=:=2+1 is returning true, but 1+2=2+1 is returning false. This is because, in the first case it is checking whether the value of 1 + 2 is same as 2 + 1 or not, and the other one is checking whether two patterns 1+2 and 2+1 are same or not. As they are not same, it returns no (false). In the case of 1+A=B+2, A and B are two variables, and they are automatically assigned to some values that will match the pattern.