Question

I am writing a program that takes in an input file from the user. The file has bunch of numbers in it and I will read the numbers in the file and create a plot based on those numbers using GD::Graph.

The first line of the file is X axis, second line of the file is Y values corresponding to X axis and third, fourth, …, etc For example:

1 2 3 4 5  2 4 5 10 14 5 6 8 12 13 

So in the above, first line is x-axis, second is y values corresponding to xaxis so this will fetch 10 points. (1, 2) (1, 5) (2, 4) (2, 6)….(4,10) (4,12) (5,14) (5, 13)

I plan on reading each line of the array and then splitting the line on spaces or tabs and storing the values in an array. So, array 1 will have x-axis, array2 will have y-axis, but how should I store 3rd, 4th, 5th, …, etc lines in an array so they become (x,y)?

Furthermore, how can I find the largest value for the first and second lines (2 arrays) so I can create a limit for my X and Y axes?

Answer 1

Whoops, misread the question, you want either an AoAoH or an AoH, depending on whether each line after the first represents a line or the are all just points to be plotted respectively. Here is how I would write it if each line in the file was to become a line in the graph:

#!/usr/bin/perl  use strict; use warnings; use List::Util qw/min max/;  my @x_points         = split ' ', scalar <>; #read in the x axis labels my ($x_min, $x_max)  = (sort { $a <=> $b } @x_points)[0,-1]; my ($y_min, $y_max)  = (0, 0);  #lines is an AoAoH, first layer are the lines to be drawn #second layer is a list of coords #third layer are the x and y coords my @lines; while (<>) {     my @y_points = split;     #if the two arrays are not the same size, we have a problem     die 'invalid file\n' unless @y_points == @x_points;      $y_min = max($y_min, @y_points);     $y_max = min($y_max, @y_points);      push @lines, [          map { { x => $x_points[$_], y => $y_points[$_] } }       0 .. $#x_points      ]; }  use Data::Dumper;  print 'x min and max $x_min $x_max\n',       'y min and max $y_min $y_max\n',       'data:\n',       Dumper(\@lines);  my $i; for my $line (@lines) {     $i++;     print 'line $i is made up of points: ',         (map { '($_->{x}, $_->{y}) ' } @$line), '\n'; } 

And here is how I would handle it if they are just points to be ploted:

#!/usr/bin/perl  use strict; use warnings; use List::Util qw/min max/;  my @x_points         = split ' ', scalar <>; #read in the x axis labels my ($x_min, $x_max)  = (sort { $a <=> $b } @x_points)[0,-1]; my ($y_min, $y_max)  = (0, 0);  #lines is an AoAoH, first layer are the lines to be drawn #second layer is a list of coords #third layer are the x and y coords my @points; while (<>) {     my @y_points = split;     #if the two arrays are not the same size, we have a problem     die 'invalid file\n' unless @y_points == @x_points;      $y_min = max($y_min, @y_points);     $y_max = min($y_max, @y_points);      push @points,         map { { x => $x_points[$_], y => $y_points[$_] } }         0 .. $#x_points; }  use Data::Dumper;  print 'x min and max $x_min $x_max\n',       'y min and max $y_min $y_max\n',       'data:\n',       Dumper(\@points);  print 'Here are the points: ',      (map { '($_->{x}, $_->{y}) ' } @points), '\n';