Perl Loop Control - Print header once 1

[Extension]

Hi,

I'm trying to control a loop so that the header is only printed once within the loop. Obviously, with my current code, the header will inherent the loop propertie; it will get printed
multiple times if there is more than one record.

Should I use labels and use the "next" function ?

Any help or guidance would be appreciated.
Thanks

open (FILE, "File.txt") or die("Error");
			
		while ( my $records = <FILE>) {
   			chomp $records;
			
			my @field=split(/\|/,$records);

			$Value0 = $field[0];
			$Value1 = $field[1];
						
			# Print header once if at least one record exists
			if ($Value1 ne '') {	
				print qq(
					------------------------- \n
					| VALUE ID | VALUE NAME | \n
				);	
			}	
			
			# Print not Null records
			if ($Value1 ne '') {	
				print qq(
					| $Value0 | $Value1 | \n
				);	
			}		 
			
		}

close FILE;

 

[mbrooks]

open (FILE, "File.txt") or die("Error");
        my $i = 0;
        while ( my $records = <FILE>) {
               chomp $records;
            
            my @field=split(/\|/,$records);

            $Value0 = $field[0];
            $Value1 = $field[1];
                        
            # Print header once if at least one record exists
            if ($Value1 ne '' && $i == 0) { 
                print qq(
                    ------------------------- \n
                    | VALUE ID | VALUE NAME | \n
                );
            }    
            
            # Print not Null records
            if ($Value1 ne '') {    
                print qq(
                    | $Value0 | $Value1 | \n
                );    
            }        
            $i++;
        }

close FILE;

M. Brooks

http://mbrooks.info

 

[mbrooks]

That was the easy way though. I suggest saving some lines by writing it this way though.

open FILE, "File.txt" or die $!;
          
my $i = 0;  
while ( <FILE> ) {
    chomp;
       
    my ( $id, $name ) = split( /\|/, $_ );
                        
    # Print header once if at least one record exists
    if ( $name ne '' && $i == 0 ) {    
        print qq{
            -------------------------
            | VALUE ID | VALUE NAME |
        };    
    } 
            
    # Print not Null records
    if ( $name ne '' ) {    
        print qq{
            | $id      | $name      |
        };    
    }        
    $i++;      
}

close FILE;

M. Brooks

http://mbrooks.info

 

[KevinADC]

why not just print the header before the loop?

 

[mbrooks]

I think he doesn't want any output if no data is available.

M. Brooks

http://mbrooks.info

 

[KevinADC]

You could be correct but I would still just print the header before the loop. But you can use the input record line number variable ($.) to see what line of the file we are on:

my $header = qq~
            -------------------------
            | VALUE ID | VALUE NAME |
            -------------------------~; 
open FILE, "File.txt" or die $!;
while ( <FILE> ) {
    print $header if [b]$. == 1[/b]; 
    chomp;
    my ($id,$name) = split(/\|/);
        print qq~
            | $id     | $name       |
        ~ if $name;    
}
close FILE;

which I am assuming means there will be at least one record. If line one has no record and is the EOF you have to check for that condition.

 

[KevinADC]

just want to say there is nothing wrong with your suggestions mbrooks, they will work fine. I should have said that previously.