printing a multidimensional array in table format

[joel]

For any number of rows and columns of a multidimensional array, I would
like my printHandler subroutine to print in table format with minimal
effort. What is the easiest way of doing this?

{
...
...
while (my (@array)=($sth->fetchrow_array()))
{
push(@result,[@array]);
}
&printHandler(@result);
}

sub printHandler
{
my $i=0;
foreach (@_)
{
print "@{$_[$i]}\n";
$i++;
}
}

current output:
4591 05-00371
149817 06-02930
15541 06-0369
827 04-00307
13406 06-01364

desired output:
4591 05-00371
149817 06-02930
15541 06-0369
827 04-00307
13406 06-01364

 

[Brian McCauley]

For any number of rows and columns of a multidimensional array, I would
like my printHandler subroutine to print in table format with minimal
effort. What is the easiest way of doing this?

{
...
...
while (my (@array)=($sth->fetchrow_array()))

All those parentheses don't really add clarity...

while (my @array = $sth->fetchrow_array )

{
push(@result,[@array]);
}

Since @array is declared within the loop (good!) you don't need to make
a copy of it, you can push a reference to @array itself as you'll get a
new @array on the next iteration.

push(@result,\@array);

&printHandler(@result);

Do you know what the & there does? If not then remove it.

As a general rule you should pass arrays to subroutines using array
references rather than unrolling the array into a list and passing each
element of the array as a separate argument.

printHandler(\@result);

BTW: have you considered using fetchall_arrayref?

sub printHandler
{
my $i=0;
foreach (@_)
{
print "@{$_[$i]}\n";
$i++;
}
}

Ouch! You put each element of @_ in turn into $_ and then ignore that
and hand carft a loop index to use as a subscript.

foreach (@_)
{
print "@{$_}\n"; # {} strictly redundant
}

Or if you'd passed an array ref...

my ($list)= @_;
foreach (@$list)
{
print "@$_\n";
}

current output:
4591 05-00371
149817 06-02930
15541 06-0369
827 04-00307
13406 06-01364

desired output:
4591 05-00371
149817 06-02930
15541 06-0369
827 04-00307
13406 06-01364

Ah, you want to print the output formatted. Perl has a "print
formatted" function ..

my ($list)= @_;
for (@$list)
{
printf "%6s %s\n",@$_;
}

Or if you feel terse..

printf "%6s %s\n",@$_ for @{+shift};

 

[joel]

Thanks for the detailed tips, much more than I expected. I have used
printf but it would require that I write code to determine the maximum
widths of each column (the number of columns and size being variable).
Not big deal but I thought that there may be an even easier way. Perl
is for doing things the easy way, right ;-)

For any number of rows and columns of a multidimensional array, I would
like my printHandler subroutine to print in table format with minimal
effort. What is the easiest way of doing this?

{
...
...
while (my (@array)=($sth->fetchrow_array()))

All those parentheses don't really add clarity...

while (my @array = $sth->fetchrow_array )

{
push(@result,[@array]);
}

Since @array is declared within the loop (good!) you don't need to make
a copy of it, you can push a reference to @array itself as you'll get a
new @array on the next iteration.

push(@result,\@array);

&printHandler(@result);

Do you know what the & there does? If not then remove it.

As a general rule you should pass arrays to subroutines using array
references rather than unrolling the array into a list and passing each
element of the array as a separate argument.

printHandler(\@result);

BTW: have you considered using fetchall_arrayref?

sub printHandler
{
my $i=0;
foreach (@_)
{
print "@{$_[$i]}\n";
$i++;
}
}

Ouch! You put each element of @_ in turn into $_ and then ignore that
and hand carft a loop index to use as a subscript.

foreach (@_)
{
print "@{$_}\n"; # {} strictly redundant
}

Or if you'd passed an array ref...

my ($list)= @_;
foreach (@$list)
{
print "@$_\n";
}

current output:
4591 05-00371
149817 06-02930
15541 06-0369
827 04-00307
13406 06-01364

desired output:
4591 05-00371
149817 06-02930
15541 06-0369
827 04-00307
13406 06-01364

Ah, you want to print the output formatted. Perl has a "print
formatted" function ..

my ($list)= @_;
for (@$list)
{
printf "%6s %s\n",@$_;
}

Or if you feel terse..

printf "%6s %s\n",@$_ for @{+shift};

 

[usenet]

I have used printf but it would require that I write code to determine the
maximum widths of each column (the number of columns and size being
variable). Not big deal but I thought that there may be an even easier way.

There is an easy way to avoid pre-calculating your maximum field
length; let the Text::Table module do it for you:

#!/usr/bin/perl
use strict; use warnings;
use Text::Table;

my $table = Text::Table->new({align => 'left'}, {align => 'left'});

$table->load( <DATA> );
print $table;

__DATA__
4591 05-00371
827 04-00307
31415927 123-456789

 

[joel]

Excellent, thanks for the suggestion!

--Joel

There is an easy way to avoid pre-calculating your maximum field
length; let the Text::Table module do it for you:

#!/usr/bin/perl
use strict; use warnings;
use Text::Table;

my $table = Text::Table->new({align => 'left'}, {align => 'left'});

$table->load( <DATA> );
print $table;

__DATA__
4591 05-00371
827 04-00307
31415927 123-456789