5.7. Perl scalar

发布时间 ： 2025-10-25 13:33:07 UTC      

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Scalar is a simple data unit.

Scalars can be an integer, floating point, character, string, paragraph, or a complete web page.

The following example demonstrates the simple application of scalars:

5.7.1. Example # 

#/usr/bin/perl$age=20；#Integer assignment$name=“Runoob”；#String $Salary=130.50#
floating point numberprint“age=$Age\\n”；print“Name=$Name\\n”；Print 'Salary'
=$salary \\n“；

Execute the above program, and the output is as follows:

Age = 20
Name = Runoob
Salary = 130.5

Digital scalar #

Scalars are usually a number or string, and the following examples demonstrate the use of different types of numeric scalars:

5.7.2. Example # 

#!/usr/bin/perl$integer=200;$negative= -300;$floating=200.340;$bigfloat=
-1.2E-23;# Octal 377 , Decimal is 255$octal=0377;# hexadecimal is FF, Decimal is
255$hexa=0xff;print"integer =$integer\\n";print"negative
=$negative\\n";print"floating =$floating\\n";print"bigfloat
=$bigfloat\\n";print"octal =$octal\\n";print"hexa =$hexa\\n";

Execute the above program, and the output is as follows:

integer = 200
negative = -300
floating = 200.34
bigfloat = -1.2e-23
octal = 255
hexa = 255

String scalar #

The following example demonstrates the use of different types of string scalars, noting the difference between the use of single and double quotes:

5.7.3. Example # 

#/ Usr/bin/perl $var="String Scalar - Beginner Tutorial!"$ Quote='I am within single quotes-
$var '$ Double="I am within double quotes - $var"$ Escape="Escape characters using - tHello,
World! ; print "var=$var n
=$double n "; print" escape=$escape n ";

Execute the above program, and the output is as follows:

Var=string scalar - rookie tutorial!
Quote=I am within single quotes - $var
Double=I am inside double quotes - string scalar - rookie tutorial!
Escape=Use escape characters - Hello, World!

Scalar operation #

The following example demonstrates the simple operation of scalars:

5.7.4. Example # 

#/ Usr/bin/perl $str="hello" 'world'# String connection $num=5+10#
Add two numbers $mul=4 * 5# Multiplying two numbers by $mix=$str$ Num# Connect string and number print "str
=$str n "; print" num=$num n "; print" mix=$mix n;

Execute the above program, and the output is as follows:

str = helloworld
num = 15
mix = helloworld15

Multiline string #

We can use single quotation marks to output multiline strings, as follows:

5.7.5. Example # 

#/ Usr/bin/perl $string='Novice Tutorial——
Learning is not only about technology, but also about dreams; Print "$string n";

Execute the above program, and the output is as follows:

Novice Tutorial
——Learning is not only about technology, but also about dreams!

You can also use the syntax format of “here” document to output multiple lines:

5.7.6. Example # 

#!/usr/bin/perlprint<   
 Execute the above program, and the output is as follows: 
 
 
 
Novice Tutorial
——Learning is not only about technology, but also about dreams!

 
 
 
 
 Special character  #  
 
 Below, we will demonstrate the application of special characters in   Perl   , such as   \__FILE__   ,   \__LINE__   , and   \__PACKAGE_\_   represent the file name, line number, and package name of the currently executing script. 
 
 Note:   \_\_   is two underscores,   \__   FILE_\_   represents two underscores before and after each.” 
 
 These special characters are separate tags and cannot be written in a string, for example: 
 
  
 
  5.7.7.  Example  #  
 
 
 
#/ Usr/bin/perlprint "file name"\__ FILE_ _ N; Print "line number"\__ LINE N;
Print 'Package Name'\__ PACKAGE_ _ N#
Unable to parse print ' _ FILE _ _ LINE _ _ _ PACKAGE_ _ n';

 
 
 
 Execute the above program, and the output is as follows: 
 
 
 
File name test.pl
Line number 4
Package name main
__ FILE____ LINE ___ PACKAGE__

 
 
 
 
 V string  #  
 
 An integer that begins with v, followed by one or more integers separated byperiods, is treated as a string text. 
 
 When you want to directly declare the numerical value of each character, thev-string provides a clearer way to construct such strings, unlike the difficult to understand method of   "\x{1}\x{14}\x{12c}\x{fa0}"   , which can be seen in the following example: 
 
 
 
 
  5.7.8.  Example  #  
 
 
 
#!/usr/bin/perl$smile=v9786;$foo=v102.111.111;$martin=v77.97.114.116.105.110;print"smile
=$smile\\n";print"foo =$foo\\n";print"martin =$martin\\n";

 
 
 
 Execute the above program, and the output is as follows: 
 
 
 
Wide character in print at test.pl line 7.
smile = &#x263a;
foo = foo
martin = Martin

 
 
 
  
                    
                
                

                    

                        

                            
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