Perl | String Operators
Operators are the foundation of any programming language. Thus, the functionality of Perl programming language is incomplete without the use of operators. A user can define operators as symbols that help to perform specific mathematical and logical computations on operands. String are scalar variables and start with ($) sign in Perl. The String is defined by user within a single quote (‘) or double quote (“) . There are different types of string operators in Perl, as follows:
- Concatenation Operator (.)
- Repetition Operator (x)
- Auto-increment Operator (++)
Concatenation Operator(.)
Perl strings are concatenated with a Dot(.) symbol. The Dot(.) sign is used instead of (+) sign in Perl. This operator takes two scalars variables as operands and combines them in a single scalar variable. Both scalars i.e left and right will convert into a single string.
Example:
Perl
# Perl program to demonstrate the# Concatenation Operator(.) in String#!/usr/bin/perl# Input first string $first_string = "Geeks";# Input second string $second_string = "forGeeks";# Implement Concatenation operator(.) $concat_string = $first_string.$second_string;# displaying concatenation string resultprint "String After Concatenation = $concat_string\n"; |
Output:
String After Concatenation = GeeksforGeeks
Repetition Operator (x)
The x operator accepts a string on its left-hand side and a number on its right-hand side. It will return the string on the left-hand side repeated as many times as the value on the right-hand side. The repetition depends on the user’s input number.
Syntax:
"String" x number_of_times
Example:
Perl
# Perl program to demonstrate the# Repetition Operator (x) in String#!/usr/bin/perl# Input a string $string = "GeeksforGeeks "; # Repetition operator(x)$str_result = $string x 5; # Display output# print string 5 times print "$str_result"; |
Output:
GeeksforGeeks GeeksforGeeks GeeksforGeeks GeeksforGeeks GeeksforGeeks
Note: Possible cases while using the Repetition Operator (x) in String as follows:
- $string xnumber : Gives Output
- $string x number : Gives Output
- $stringxnumber : Gives Error(where no space between string and x)
- $stringx number : Gives Error(where no space between string and x)
Important Point to Remember: Both the Concatenation and Repetition operator can be used with assignment(=) operator as follows:
- Concatenation Assignment Operator (.=)
- Repetition Assignment Operator (x=)
Example:
Perl
# Perl program to demonstrate the# Concatenation and Repetition # Assignment Operator in String #!/usr/bin/perl # Input first string $string1 = "Geeks"; # Input second string $string2 = "forgeeks"; $combine = $string1; # combine two string function (.=)$combine .= $string2; # Display resultprint $combine;$str_result = "Sudo_Placements";# Repetition operator(x)$str_result x= 5; # Display output# print string 5 timesprint "\n$str_result"; |
Output:
Geeksforgeeks Sudo_PlacementsSudo_PlacementsSudo_PlacementsSudo_PlacementsSudo_Placements
Auto-increment Operator (++)
This operator can also apply to strings. It is a unary operator thats why it will only take a single operand as string. The last character of the operand(i.e string) will increment by one using the ASCII values of characters. The important point to remember about ++ operator that if the string ends with ‘z or”Z’ then the result of ++ operator will be ‘a’ or ‘A’ respectively but the letter to the left of it will also increment by one as well.
Example:
Perl
# Perl program to demonstrate # Auto-increment Operator (++) #!/usr/bin/perl # Input string $st = "AYY"; $st++;# Display outputprint "After ++ : $st";# Once again $st++;# Display outputprint "\nAgain After ++ : $st"; |
Output:
After ++ : AYZ Again After ++ : AZA
What will happen if we pass an Alpha Numeric string with a number at last and try to increment it ? The number will be incremented by one just like it happened with the previous example –
Perl
#!/usr/bin/perl# your code here$str = "ABC8";$str++;print($str); |
ABC9
Time Complexity – O(1)
Auxiliary Space – O(1)
