Comparison Operators on String
In Common Lisp, strings are vectors, which are one-dimensional arrays of characters. Except for the double quotation character (“) and the escape character (\), every character supported by the character set can be contained between double quotes to form a string. Like Character, the string also has two sets of Comparison Operators, one is Case-sensitive and the other is Case-insensitive.
So, to check whether the two Strings are equal are not, the following are some comparison Functions that can be used.
| Case-sensitive | Case-insensitive | Explanation |
|---|---|---|
| STRING= | STRING-EQUAL | Checks if the operands’ values are all equal; if they are, the condition is true. |
| STRING/= | STRING-NOT-EQUAL | Checks if the operands’ values are all unequal; if they are, the condition is true. |
| STRING< | STRING-LESSP | If string1 is smaller than string2, the condition is true; otherwise, the condition is false. |
| STRING<= | STRING-NOT-GREATERP | If any of the left operands’ values are less than or equal to the value of the following right operand, the condition is true. |
| STRING> | STRING-GREATERP | If string1 is greater than string2, the condition is true; otherwise, the condition is false. |
| STRING>= | STRING-NOT-LESSP | If any left operand’s value is more than or equal to its right operand’s value, the condition is true. |
Example 1: Case Sensitive Comparison.
Lisp
(write (STRING= "gfg" "GFG")) (terpri) (write (STRING> "gfg" "GFG")) (terpri) (write (STRING< "gfg" "GFG")) |
Output: When running the above code, the output is as follows.
NIL 0 NIL
Example 2: Case-insensitive Comparison.
Lisp
(write (STRING-EQUAL "gfg" "GFG")) (terpri) (write (STRING-GREATERP "gfg" "GFG")) (terpri) (write (STRING-LESSP "gfg" "GFG")) |
Output: Comparison OperatorsWhen running the above code, the output is as follows.
T NIL 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.