Comparison Operators on Character
Characters are not supported by numerical comparison functions and operators such as < and >. Other than that, Two sets of functions in Common LISP are used. The first set is case-sensitive, whereas the second is not case-sensitive or (case-insensitive).
Following are some comparison functions that may be used to see whether the two characters are equivalent or not equal.
| Case-Sensitive | Case-Insensitive | Explanation |
|---|---|---|
| CHAR= | CHAR-EQUAL | Checks if the operands’ values are all equal; if they are, the condition is true. |
| CHAR/= | CHAR-NOT-EQUAL | Checks if the operands’ values are all different or not; if they aren’t, the condition is true. |
| CHAR< | CHAR-LESSP | If the character1 is smaller than character2, the condition is true; otherwise, the condition is false. |
| CHAR<= | CHAR-NOT-GREATERP | If any of the left character’s values are less than or equal to the value of the following right character, the condition is true. |
| CHAR> | CHAR-GREATERP | If character1 is greater than character2, the condition is true; otherwise, it is false. |
| CHAR>= | CHAR-NOT-LESSP | If any left character’s value is more than or equal to its right character’s value, the condition is true. |
Example 1: Case sensitive Comparison
Lisp
(write (CHAR= #\a #\A)) (terpri) (write (CHAR> #\b #\a)) (terpri) (write (CHAR< #\A #\a)) |
Output: When running the above code, the output is as follows.
NIL T T
Example 2: Case-insensitive Comparison
Lisp
(write (CHAR-EQUAL #\a #\A)) (terpri) (write (CHAR-EQUAL #\a #\b)) (terpri) (write (CHAR-LESSP #\a #\b #\c)) (terpri) (write (CHAR-GREATERP #\a #\b #\c)) |
Output: When running the above code, the output is as follows.
T NIL T NIL
LISP – Comparison Operators on Characters & Strings
The contents of a field are compared to the contents of another field or a constant using Comparison operators. In Simple words, comparator operators are used to compare whether the two or more different values are equal or not.