Perl | print operator

The print function is one of the most commonly used functions in Perl, allowing you to output data to the console or a file. This tutorial will walk you through the basics of using the print operator in Perl.

Basic Usage

Simple Print: To print a string or variable to the console:
```
print "Hello, World!";
```
Printing Variables: You can print variables by simply placing them inside the print statement:
```
my $name = "Alice";
print "Hello, $name!";
```
Printing Multiple Items: print can handle multiple items separated by commas:
```
my $name = "Alice";
my $age = 30;
print "Name:", $name, " Age:", $age;
```

Special Characters

Newline (\n): To print a newline, you can use the \n character:
```
print "This is the first line.\nThis is the second line.";
```
Tab (\t): To print a tab space:
```
print "Name:\tAlice";
```

Printing to a File

File Handles: To print to a file, you'll need to use a file handle:
```
open(my $fh, '>', 'file.txt') or die "Could not open file 'file.txt' $!";
print $fh "Writing this to the file.";
close($fh);
```
In the above code:
- We open file.txt for writing (> means write mode).
- We then print to the file using the $fh file handle.
- Finally, we close the file handle.

File Handle with Select: You can set a file handle as the default for print:

open(my $fh, '>', 'file.txt') or die "Could not open file 'file.txt' $!";
select $fh;
print "This will go to the file.";
select STDOUT;  # Switch back to standard output
close($fh);

Formatting

While print itself doesn't offer formatting like printf in C, Perl does have printf and sprintf functions for formatted output. For instance:

my $name = "Alice";
my $age = 30;
printf "Name: %s, Age: %d", $name, $age;

Combining with Other Functions

print can be combined with other functions to produce dynamic output:

Array Elements:

my @fruits = ("apple", "banana", "cherry");
print "I love $fruits[1]s!";

This will print: I love bananas!

Expressions:

my $result = 5 + 5;
print "The result is $result";

Conclusion

The print function is a fundamental tool in Perl for outputting data. While it offers a straightforward mechanism for printing to the console and files, combining it with other functions and features in Perl provides powerful capabilities for displaying data in various ways.

print "Hello, World!\n";  # Outputs: Hello, World!

open my $file_handle, '>', 'output.txt' or die "Cannot open file: $!";
print $file_handle "Writing to file\n";
close $file_handle;

print "Also printing to STDOUT\n";

my $name = "John";
my $age = 25;
printf "Name: %-10s Age: %d\n", $name, $age;  # Outputs: Name: John       Age: 25

my $first_name = "John";
my $last_name = "Doe";
print "Full name: " . $first_name . " " . $last_name . "\n";  # Outputs: Full name: John Doe

my $variable = "Hello";
print $variable, " World!\n";  # Outputs: Hello World!

print "The answer is ", 42, "!\n";  # Outputs: The answer is 42!

print "This will not end with a newline";
print "This will be on the same line\n";