print("@input") VS print(@input)

[sixtyfootersdude]

Good Morning!

I am just starting to learn perl and I am somewhat mistifide about when I should do:

print("@input");

and when I should do:

print(@input)

Coming from Java I would do:

for(int i=0; i<array.length;i++){
  System.out.print(array[i]);
System.out.println();
 

I cannot figure out why the print with the quotations adds leading spaces onto the output. See this example:

#! /usr/bin/perl
 
use strict;
use warnings;
 
my @input=<>;
 
for my $input (@input){
    # $input=reverse($input);
}
 
print("===\nIn Quotes:\n");
print("@input");
 
print("\n\n===\nNOT In Quotes\n");
print(@input);
 
print "End Program\n";
 

Produces this:

jake-summers-computer:~/All Work/School Work/NLP/Ass2/Q3 jsummers$ cat SampleInput 
Hello Everyone I am Jake.  
This is the second line to the intro.  
 
Fourth line (third line is empty)jake-summers-computer:~/All Work/School Work/NLP/Ass2/Q3 jsummers$ 
jake-summers-computer:~/All Work/School Work/NLP/Ass2/Q3 jsummers$ 
jake-summers-computer:~/All Work/School Work/NLP/Ass2/Q3 jsummers$ 
jake-summers-computer:~/All Work/School Work/NLP/Ass2/Q3 jsummers$ 
jake-summers-computer:~/All Work/School Work/NLP/Ass2/Q3 jsummers$ ./line-reverseV2.pl < SampleInput 
===
In Quotes:
Hello Everyone I am Jake.  
 This is the second line to the intro.  
 
 Fourth line (third line is empty)
 
===
NOT In Quotes
Hello Everyone I am Jake.  
This is the second line to the intro.  
 
Fourth line (third line is empty)End Program
jake-summers-computer:~/All Work/School Work/NLP/Ass2/Q3 jsummers$ 
 

Where is the space in front of " Fourth line (third line is empty)" coming from?

[toolic]

The short answer is... use the quotes when you want to print an additional
single space character between each element of your array.

I think a trivial example will help illustrate the difference between your
2 cases:

use strict;
use warnings;
 
my @inputs = ('a', 'b', 'c');
 
print @inputs;
print "\n";
 
print "@inputs";
print "\n";
 
__END__
abc
a b c
 

This behavior is described here:
http://perldoc.perl.org/perlvar.html

Search for LIST_SEPARATOR and OUTPUT_FIELD_SEPARATOR.
This will describe how to further control printed output, if needed.

The quotes are adding a space between all elements of you input
array. Since each element of your array has a trailing newline character,
all element of your array appear on separate lines of the output.
Apparently, your array has 4 elements (lines). The last 3 will have
a leading space.

[sixtyfootersdude]

OOOOOOOOOOOOOOOOO. Ok that makes sense. Thanks for the reply.

Jake