A string is a set of characters. String are enclosed in double-quotes.
Example:
"hello geek","java","python" etc
Example: LISP program to display strings
Lisp
;edisplay hello geek
(write-line "Hello Geek")
;display
(write-line "Welcome to java")
Output:
Hello Geek
Welcome to java
String Comparison Functions:
Used to compare two strings. Further they can be divided into two categories. They are
Case Sensitive Functions:
These functions can be represented by mathematical symbols.
| Symbol | Name | Syntax | Description |
|---|
| = | equal to | string= | This operator checks if the values of the operands are all equal or not, if yes then the condition becomes true(T). otherwise it returns NIL |
|---|
| /= | not equal to | string/= | This operator checks if the values of the operands are all different or not, if values are not equal then the condition becomes true(T). otherwise, it returns NIL |
|---|
| > | greater than | string> | This operator checks if the values of the operands are monotonically increasing. |
|---|
| < | less than | string< | This operator checks if the values of the operands are monotonically decreasing. |
|---|
| >= | greater than or equal to | string>= | This operator checks if the value of any left operand is less than or equal to the value of its right operand, if yes then the condition becomes true. |
|---|
| <= | less than or equal to | string<= | This operator checks if the value of any left operand is greater than or equal to the value of the next right operand, if yes then the condition becomes true. |
|---|
Example: LISP program that demonstrates string case sensitive functions
Lisp
; case-sensitive comparison - equal to
(write (string= "Hello Geeks" "Hello Geeks"))
;new line
(terpri)
; case-sensitive comparison - equal to
(write (string= "Hello Geeks" "HelloGeeks"))
;new line
(terpri)
; case-sensitive comparison - not equal to
(write (string/= "Hello Geeks" "Hello Geeks"))
;new line
(terpri)
; case-sensitive comparison - not equal to
(write (string/= "Hello Geeks" "HelloGeeks"))
;new line
(terpri)
; case-sensitive comparison - greater than
(write (string> "Hello Geeks" "Python"))
;new line
(terpri)
; case-sensitive comparison - less than
(write (string< "Hello Geeks" "java"))
;new line
(terpri)
; case-sensitive comparison - greater than or equal to
(write (string>= "Hello Geeks" "Python"))
;new line
(terpri)
; case-sensitive comparison - less than or equal to
(write (string<= "Hello Geeks" "java"))
;new line
(terpri)
Output:
T
NIL
NIL
5
NIL
0
NIL
0
Case INSENSITIVE FUNCTIONS
These functions can be represented by expressions.
| Name | Syntax | Description |
|---|
| equal | string-equal | This operator checks if the values of the operands are all equal or not, if yes then the condition becomes true(T). Otherwise, it returns NIL |
|---|
| not equal | string-not-equal | This operator checks if the values of the operands are all different or not, if values are not equal then the condition becomes true(T). Else, it returns NIL |
|---|
| greater than | string-greaterp | This operator checks if the values of the operands are monotonically increasing. |
|---|
| less than | string-lessp | This operator checks if the values of the operands are monotonically decreasing. |
|---|
| greater than or equal to | string-not-lessp | This operator checks if the value of any left operand is less than or equal to the value of its right operand, if yes then the condition becomes true. |
|---|
| less than or equal to | string-not-greaterp | This operator checks if the value of any left operand is greater than or equal to the value of the next right operand, if yes then the condition becomes true. |
|---|
Example: Lisp program that demonstrates case insensitive functions
Lisp
; case-sensitive comparison - equal to
(write (string-equal "Hello Geeks" "Hello Geeks"))
;new line
(terpri)
; case-sensitive comparison - equal to
(write (string-equal "Hello Geeks" "HelloGeeks"))
;new line
(terpri)
; case-sensitive comparison - not equal to
(write (string-not-equal "Hello Geeks" "Hello Geeks"))
;new line
(terpri)
; case-sensitive comparison - not equal to
(write (string-not-equal "Hello Geeks" "HelloGeeks"))
;new line
(terpri)
; case-sensitive comparison - greater than
(write (string-greaterp "Hello Geeks" "Python"))
;new line
(terpri)
; case-sensitive comparison - less than
(write (string-lessp "Hello Geeks" "java"))
;new line
(terpri)
; case-sensitive comparison - greater than or equal to
(write (string-not-lessp "Hello Geeks" "Python"))
;new line
(terpri)
; case-sensitive comparison - less than or equal to
(write (string-not-greaterp "Hello Geeks" "java"))
;new line
(terpri)
Output:
T
NIL
NIL
5
NIL
0
NIL
0