question to a complex structure of hash/array

buchi2 has asked for the wisdom of the Perl Monks concerning the following question:

Hello!

I have to plot several diagramms and want to do it with chart::gnuplot.

It needs the x and y as arrayref with

xdata => \@xarray,
ydata => \@yarray,
[download]

I want to plot the diagramms with a loop.
Where the data is coming from is different for the loop elements, so that I have to put it before into a structure, over it then I can loop.
Not every index is filled. First I try to differ between and choose therefore i and ii, but then I dicide to use only the index i and skip the unfilled indexe during plotting.
This is the part of my code:

# die Plotfelder/-hashe belegen und hash istart
$ii = -1;
for ($i = 0; $i <= $#yfeld; $i++) {
#   next if ($yfeld[$i] == 0);
   $ii = $ii + 1;
   print "$i $ii ";
   push(@ploty,$yfeld[$i]);
   push @{$istart{$ii}}, $istart[$i];
   push @{$ianz{$ii}}, $ianz[$i];
   if ($xfeld[$i] eq 'x') {
      push @{$plotx{$ii}}, @xfix;
      print "x\n";
   } elsif ($xfeld[$i] eq 'y') {
      push @{$plotx{$ii}}, @yfix;
      print "y\n";
   } else {
      push @{$plotx{$ii}}, $fnfeld[$xfeld[$i]]->{'fn'};
      print "$xfeld[$i]\n";
   }
}
print "\n";
print "2 $plotx{2}[3]\n";
print "3 $plotx{3}[3]\n";
print "5 $plotx{5}[3]\n"; # ?
print "6 $plotx{6}[3]\n";
print "7 $plotx{7}[3]\n"; # ?
print "8 $plotx{8}[3]\n"; # ?
print "9 $plotx{9}[3]\n";
[download]

The prints in the loop are for checking. It seems all correct.

I ommit the index 0, 1, 4, because it is empty (0 in the first print-block).
But the print-check at the end of my code snippet gives this:

2 3.640000E-04
3 3.640000E-04
Use of uninitialized value in concatenation (.) or string at test.pl l
+ine 590.
5 
6 3.640250E-04
Use of uninitialized value in concatenation (.) or string at test.pl l
+ine 592.
7 
Use of uninitialized value in concatenation (.) or string at test.pl l
+ine 593.
8 
9 3.640000E-04
[download]

So it means, that something goes wrong, where I want to assign the fnfeld to my plotx.
I read this "References quick reference" and my brain has meanwhile several knots to thinking about this. But I have no idea, what is wrong with the syntax.
I think, it is the reference, because I use it successfull for plotting:

ydata => $fnfeld[$ploty[$ii]]->{'fn'},
[download]

But how can I assing the values from the array of hashes, which contains an array?

Regards, buchi

Comment on question to a complex structure of hash/array Select or Download Code

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Re: question to a complex structure of hash/array by thanos1983 (Parson) on Aug 08, 2017 at 12:01 UTC
Hello buchi2, Can you provide us a working / compiling piece of code. I would like to test your code but I am not able because I am missing parts. Regarding the for loop that you have...you can write it in a Perl way also: `for ($i = 0; $i <= $#yfeld; $i++)` Assuming that `$#yfeld` is an array `@yfeld`. `for my $i (0 .. $#yfeld)` I also do not understand why you instantiate `$ii = -1;` and on the next step 3 lines after you are adding 1 `$ii = $ii + 1;` which will result to 0. You can get this value from your for loop why you need to apply this calculation? Unless I am missing something here, that is hidden in the rest of the code that is missing. Looking forward to your update, BR Seeking for Perl wisdom...on the process of learning...not there...yet!	[reply] [d/l] [select]
Re^2: question to a complex structure of hash/array by buchi2 (Acolyte) on Aug 09, 2017 at 08:02 UTC
Hello! >I also do not understand why you instantiate $ii = -1; and on the next step 3 lines after you are adding 1 $ii = $ii + 1; which will result to 0. You can get this value from your for loop why you need to apply this calculation? I removed this now with $ii and $i and use only $i. I had e.g. (0 1 2 3 0 0 0 7 0 9) as an input and my first try was, to keep these structure and take another structure, which only contain the places, which are not 0. Regards, buchi	[reply]
Re: question to a complex structure of hash/array by BillKSmith (Monsignor) on Aug 08, 2017 at 15:48 UTC
When $xfeld$I is equal to either an 'x' or a 'y', You push an array into the output. Otherwise you push a scalar. Your final prints expect the array. Your first print section shows that you stored the scalar when $i was equal to 0,1,4,5,7, and 8. Your final section would fail for all of these, but you do not try to print for $i equal to 0, 1, or 4. It does fail when $i is equal to 5, 7, and 8. Your print works as expected for the other cases (2, 3, 6, and 9). I cannot suggest a solution, because you have not shown us any data. UPDATE: Added code which duplicates the posted output. Removed irrelevant code from and added initialization to originally posted code. A dump of the output hash %plotx reveals what happens. use strict; use warnings; use Data::Dumper; # Data infered from posted output. my @xfeld = qw(0 0 y y 0 5 x 5 5 y); my @xfix = qw( UNKNOWN_x_0 UNKNOWN_x_1 UNKNOWN_x_2 3.640250E-4 ); my @yfix = qw( UNKNOWN_y_0 UNKNOWN_y_1 UNKNOWN_y_2 3.640000E-4 ); my @fnfeld = ( {fn => 'UNKNOWN_n_0',}, {fn => 'UNKNOWN_n_1',}, {fn => 'UNKNOWN_n_2',}, {fn => 'UNKNOWN_n_3',}, {fn => 'UNKNOWN_n_4',}, {fn => 'UNKNOWN_n_5',}, {fn => 'UNKNOWN_n_6',}, {fn => 'UNKNOWN_n_7',}, {fn => 'UNKNOWN_n_8',}, {fn => 'UNKNOWN_n_9',}, ); my @yfeld; $#yfeld = $#xfeld; my %plotx; my $ii = -1; for (my $i = 0; $i <= $#yfeld; $i++) { $ii = $ii + 1; print "$i $ii "; if ($xfeld[$i] eq 'x') { push @{$plotx{$ii}}, @xfix; print "x\n"; } elsif ($xfeld[$i] eq 'y') { push @{$plotx{$ii}}, @yfix; print "y\n"; } else { push @{$plotx{$ii}}, $fnfeld[$xfeld[$i]]->{'fn'}; # The Previous statement stores only one value. # The failing prints expects at least four. print "$xfeld[$i]\n"; } } print "\n"; print "2 $plotx{2}[3]\n"; print "3 $plotx{3}[3]\n"; print "5 $plotx{5}[3]\n"; # Array element does not exist print "6 $plotx{6}[3]\n"; print "7 $plotx{7}[3]\n"; # Array element does not exist print "8 $plotx{8}[3]\n"; # Array element does not exist print "9 $plotx{9}[3]\n"; print Dumper(\%plotx); OUTPUT: 0 0 0 1 1 0 2 2 y 3 3 y 4 4 0 5 5 5 6 6 x 7 7 5 8 8 5 9 9 y 2 3.640000E-4 3 3.640000E-4 Use of uninitialized value in concatenation (.) or string at buchi2.pl + line 41. 5 6 3.640250E-4 Use of uninitialized value in concatenation (.) or string at buchi2.pl + line 43. 7 Use of uninitialized value in concatenation (.) or string at buchi2.pl + line 44. 8 9 3.640000E-4 $VAR1 = { '1' => [ 'UNKNOWN_n_0' ], '8' => [ 'UNKNOWN_n_5' ], '6' => [ 'UNKNOWN_x_0', 'UNKNOWN_x_1', 'UNKNOWN_x_2', '3.640250E-4' ], '3' => [ 'UNKNOWN_y_0', 'UNKNOWN_y_1', 'UNKNOWN_y_2', '3.640000E-4' ], '2' => [ 'UNKNOWN_y_0', 'UNKNOWN_y_1', 'UNKNOWN_y_2', '3.640000E-4' ], '9' => [ 'UNKNOWN_y_0', 'UNKNOWN_y_1', 'UNKNOWN_y_2', '3.640000E-4' ], '7' => [ 'UNKNOWN_n_5' ], '5' => [ 'UNKNOWN_n_5' ], '0' => [ 'UNKNOWN_n_0' ], '4' => [ 'UNKNOWN_n_0' ] }; [download] Bill	[reply] [d/l]
Re^2: question to a complex structure of hash/array by choroba (Cardinal) on Aug 08, 2017 at 15:55 UTC
> push an array `push @results, @array;` extends @results by the elements of @array, it doesn't "push an array", as all the elements of an array must be scalars. You can push an array reference, though: `push @results, \@array;` [download] ($q=q:Sq=~/;[c](.)(.)/;chr(-\|\|-\|5+lengthSq)`"S\|oS2"`map{chr \|+ord }map{substrSq`S_+\|`\|}3E\|-\|`7**2-3:)=~y+S\|`+$1,++print+eval$q,q,a, [download]	[reply] [d/l] [select]
Re^3: question to a complex structure of hash/array by buchi2 (Acolyte) on Aug 09, 2017 at 04:28 UTC
Hello! Thanx to all. I will try to give a running code. With the dumper there is the problem, that are some hundret values. `ydata => $fnfeld[$ploty[$ii]]->{'fn'},` [download] This call to gnuplot is working. But this not: `push @{$plotx{$ii}}, $fnfeld[$xfeld[$i]]->{'fn'}; . . . xdata => $plotx{$ii},` [download] It is empty. I will try to create a short standalone code. Regards buchi	[reply] [d/l] [select]
Re^3: question to a complex structure of hash/array by buchi2 (Acolyte) on Aug 09, 2017 at 07:55 UTC
Hello! >push @results, @array; extends @results by the elements of @array, it doesn't "push an array", as all the elements of an array must be scalars. You can push an array reference, though: yes, thanks, so to getting it keep as an array, I push it to a hash. e.g. `my %plotx; my $i; my @xfix; push @{$plotx{$i}}, @xfix;` [download] Regards, buchi	[reply] [d/l]
Re^4: question to a complex structure of hash/array by buchi2 (Acolyte) on Aug 09, 2017 at 08:10 UTC
Re: question to a complex structure of hash/array by Anonymous Monk on Aug 08, 2017 at 14:17 UTC
Perl debugging 101: `use Data::Dumper; print Dumper(\@plotx);` [download]	[reply] [d/l]
Re: question to a complex structure of hash/array by Anonymous Monk on Aug 08, 2017 at 14:38 UTC
Just taking a stab in the dark, I'm thinking that this: `push @{$plotx{$ii}}, $fnfeld[$xfeld[$i]]->{'fn'};` possibly should be this instead: `push @{$plotx{$ii}}, @{$fnfeld[$xfeld[$i]]->{'fn'}};` But the whole thing seems needlessly complicated. Agree with thanos that it would help if we could see more of your program, particularly the call to Gnuplot.	[reply]
Re^2: question to a complex structure of hash/array by buchi2 (Acolyte) on Aug 09, 2017 at 05:05 UTC
Hello! `push @{$plotx{$ii}}, @{$fnfeld[$xfeld[$i]]->{'fn'}};` [download] results: Can't use an undefined value as an ARRAY reference at testl.pl line 585 Regards buchi	[reply] [d/l]
Re^3: question to a complex structure of hash/array by buchi2 (Acolyte) on Aug 11, 2017 at 08:49 UTC
Hello! I dont know, what was going wrong before, but the line `push @{$plotx{$ii}}, @{$fnfeld[$xfeld[$i]]->{'fn'}};` [download] is working now. :) Thanx. Regards, buchi	[reply] [d/l]