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#PERL PRINT HOW TO#
#PERL PRINT CODE#

Perl enables you to do this by specifying value fieldsĮach value field specifies a value: the name of a scalar variable,įor example, or an expression. Stored in scalar variables or array variables to produce readable Of course, the main reason to use print formats is to format values The print format to use, the Perl interpreter would have tried to use a print format named STDOUT when executing the call to write in line 4, because the call to write is writing to the standard output file Name as the file variable being written to. The Perl interpreter assumes that the print format to use has the same If you don't specify a print format by assigning to $~, Lines 6-10 contain the definition of the print format MYFORMAT. Line 4 calls write, which sends the text defined in MYFORMAT Tells the Perl interpreter that MYFORMAT is the print String MYFORMAT to the system variable $~. Line 3 of this program assigns the character Listing 11.1 is an example of a simple program that displays output

Set the system variable $~ to the format you want.

To display output using a print format, you need to do two things: However, it usually is best to cluster them eitherĪt the beginning or the end of the program.

#PERL PRINT CODE#

In program code (even, for example, in the middle of a conditional Like subroutines, print-format definitions can appear anywhere

This line can contain nothing else thereĬan be no white space, and the period must be the first character Two lines containing = characters, and the lineĪ print-format definition is terminated with a line containingĪ period character. MYFORMAT example, there are three lines of text printed: These lines are sometimes called picture lines. Text that are to be printed when the print format is utilized The lines_of_output consists of one or more lines of This name must start with anĪlphabetic character and can consist of any sequence of letters, Is a placeholder for the name of the print format being defined The special keyword format tells the Perl interpreter that theįollowing lines are a print-format definition. The following is an example of a simple print format:

#PERL PRINT HOW TO#

How to use the built-in function printf.How to specify page headers and the page length.Which value-field formats are available.How to add formatted values to a print format.How to define a print format (also sometimes known as a "picture.Today's lessonĭescribes how to produce formatted output. Perl also enables you to produce formatted output, using printįormats and the built-in function write.

Print function, which writes raw, unformatted text to The Perl programs you've seen so far produce output using the Day 11 - Formatting Your Output Chapter 11 Formatting Your Output