On 9/30/09 Wed Sep 30, 2009 11:33 AM, "Bruce Ferrell" <bferr...@baywinds.org> scribbled:
> > > Shawn H Corey wrote: >> Bruce Ferrell wrote: >>> I have a database (mysql if it matters) and I can select columns and >>> rows from it no problem. what I can't quite seem to see how to do is to >>> take the columns I can select and put them into a 2 dimensional array. >>> >>> I tried this: >>> >>> @data = $sth->fetchrow_array(); >>> >>> and it got a two dimensional array of one element each and this: >>> >>> @rtn = $sth->fetchrow_array(); >>> push(@data,@rtn) seems to get me a giant 1 dimensional array. >>> >>> I'm sort of at a loss >>> >>> TIA >>> >>> Bruce >>> >> >> You have to create an array of arrays. >> >> push @data, [ @rtn ]; >> >> See: >> perldoc perldsc http://perldoc.perl.org/perldsc.html >> perldoc perllol http://perldoc.perl.org/perllol.html >> perldoc perldata http://perldoc.perl.org/perldata.html >> >> > OK if I read these right and I understand the results of my experiments > correctly, this: > > @rtn = $sth->fetchrow_array(); > > is giving me an array with two elements and this: > > push @data, [ @rtn ]; > > is giving me an array of 2 element arrays. Not good as what I want is 2 > arrays each the length of the total rows returned. What it seems I need > to do is something like this: > > my ( $current_level, $time ) = $sth->fetchrow_array(); > > push @data[0][#]->$current_level; > push @data[1][#]->$time; > > ... repeat until out of rows > > Is that correct notation to add the variable to the end of the array(s)? No. Apparently what you want is push( @{$data[0]}, $current_level); push( @{$data[1]}, $time); You could also define two separate arrays: my @current_levels; my @times; and fill them with similar statements: push( @current_levels, $current_level); push( @times, $time); and put links to them in @data: my @data = ( \...@current_levels, \...@times ); Some would consider that a poor choice of data structure, as your pairs of elements are only associated by using a common index. for my $row ( 0..$#{$data[0]} ) { my $level = $data[0]->[$row]; my $time = $data[1]->[$row]; } There is no guarantee that the two arrays even have the same number of elements. Most people would prefer Shawn's scheme: push( @data, [ $current_level, $time ]); The two data elements are very closely associated. You can sort them by time and extract them together: for my $row ( sort {$a->[1] <=> $b->[1]} @data ) { my{ $level, $time ) = @$row; } which is much more difficult to do in the first case. So why do you think you need to have two arrays the same length containing data from different rows? -- To unsubscribe, e-mail: beginners-unsubscr...@perl.org For additional commands, e-mail: beginners-h...@perl.org http://learn.perl.org/
