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: Execute the above program, and the output is as follows: Scalars are usually a number or string, and the following examples demonstrate the use of different types of numeric scalars: Execute the above program, and the output is as follows: The following example demonstrates the use of different types of string scalars, noting the difference between the use of single and double quotes: Execute the above program, and the output is as follows: The following example demonstrates the simple operation of scalars: Execute the above program, and the output is as follows: We can use single quotation marks to output multiline strings, as follows: Execute the above program, and the output is as follows: You can also use the syntax format of “here” document to output multiple lines: Execute the above program, and the output is as follows: Below, we will demonstrate the application of special characters in Note: These special characters are separate tags and cannot be written in a string, for example: Execute the above program, and the output is as follows: 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 Execute the above program, and the output is as follows:
最近几年来，地理信息系统无论是在理论上还是应用上都处在一个飞速发展的阶段。 GIS被应用于多个领域的建模和决策支持，如城市管理、区划、环境整治等等，地理信息成为信息时代重要的组成部分之一； “数字地球”概念的提出，更进一步推动了作为其技术支撑的GIS的发展。 与此同时，一些学者致力于相关的理论研究，如空间感知、空间数据误差、空间关系的形式化等等。 这恰好说明了地理信息系统作为应用技术和学科的两个方面，并且这两个方面构成了相互促进的发展过程。 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“；
Age = 20 Name = Runoob Salary = 130.5
Digital scalar #
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";
integer = 200 negative = -300 floating = 200.34 bigfloat = -1.2e-23 octal = 255 hexa = 255
String scalar #
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 ";
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 #
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;
str = helloworld num = 15 mix = helloworld15
Multiline string #
5.7.5. Example #
#/ Usr/bin/perl $string='Novice Tutorial—— Learning is not only about technology, but also about dreams; Print "$string n";
Novice Tutorial ——Learning is not only about technology, but also about dreams!
5.7.6. Example #
#!/usr/bin/perlprint<
Novice Tutorial ——Learning is not only about technology, but also about dreams!
Special character #
Perl , such as \__FILE__ , \__LINE__ , and \__PACKAGE_\_ represent the file name, line number, and package name of the currently executing script. \_\_ is two underscores, \__ FILE_\_ represents two underscores before and after each.” 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';
File name test.pl Line number 4 Package name main __ FILE____ LINE ___ PACKAGE__
V string #
"\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";
Wide character in print at test.pl line 7. smile = ☺ foo = foo martin = Martin