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--- tutorial:data [2012/08/07 14:43] – [Handling polymake objects] paffenholz
+++ user_guide:tutorials:data [2019/02/11 16:43] – ↷ Links adapted because of a move operation oroehrig
@@ Line 4: / Line 4: @@
 ===== Handling polymake objects =====
+Let us take this nice example object:
+  > $p = cube(3);
+To store polymake objects use the command
+  > save($p,"myPolyObject.poly");
+This silently overwrites existing files.
 polymake objects that are stored in polymake's own XML file format can be loaded via
-  $p=load("myPolyObject.poly");
+  > $p=load("myPolyObject.poly");
-If you did not start ''polymake'' in the directory containing your object, it is necessary to add the relative path, e.g.
+If you did not start ''polymake'' in the directory containing your object, it is necessary to add the relative or absolute path, e.g.
   $p=load("MyFolder/myPolyObject.poly");
-To store polymake objects use the command
+TAB completion like in a usual UNIX shell supports you in navigating through the file system.
-  save($p,"myPolyObject.poly");
 **Note:** If you load a polymake object and compute new properties, these properties will automatically be added to the original XML-file at the end of the session. You can suppress this with the command
-  $p->dont_save;
+  > $p->dont_save;
-called prior to leaving the session (but after the last compuation with $p).
+called prior to leaving the session (but after the last computation with $p).
+If you want to store a collection of objects into a single file, there is an [[..:howto:tarballs|extra tutorial]] for you.
 ===== Handling complex data types =====
-It is also possible to store complex data structures in XML format via ''save_data'', e.g.
+Apart from the full objects, you can also persistently store arbitrary data structures like matrices or graphs in XML format via ''save_data'', e.g.
-  $s=new Set<Int>(1,2,3,4);
+  > $s=new Set<Int>(1,2,3,4);
-  save_data($s,"mySet.poly");
+  > save_data($s, "mySet.poly", "My very own set.");
+The description text is optional; it can be an arbitrary text, even stretching over several lines.
 To load such files just type
-  $s=load_data("mySet.poly");
+  > $s=load_data("mySet.poly");
+===== Saving visualized objects =====
+Furthermore, most visualization methods provide an option to save the visualized object in a suitable format. Consult the [[user_guide:intro_tutorial#getting_help|F1 help]] for information on the file format and further options.
+To save the cube visualized via JReality in a new file called ''mycube.bsh'', do this:
+<code>jreality(cube(3)->VISUAL,File=>"mycube");</code>
+To save the cube as a TiKz file named ''mycube.tikz'' that you can e.g. import in a LaTeX document, do this instead:
+<code>tikz(cube(3)->VISUAL,File=>"mycube");</code>
 ===== Handling arbitrary files =====
@@ Line 33: / Line 51: @@
 0 1 1
 1 1 1
+For the sake of the example, let's create this file:
+  > open(my $f, '> points.txt'); print $f "1 0 0 0\n1 1 0 0\n1 0 1 0\n1 1 1 0\n1 0 0 1\n1 1 0 1\n1 0 1 1\n1 1 1 1\n"; close $f;
 To read this file try the following:
-  open(INPUT, "< points.txt");
+  > open(INPUT, "< points.txt");
-  while(<INPUT>){
+  > while(<INPUT>){
-    print $_;
+  >   print $_;
-  }
+  > }
-  close(INPUT);
+  > close(INPUT);
 ''<INPUT>'' is a perl input iterator reading the file line by line.  Variable ''$_'' refers to the current line within this loop; it has a plain string value.\\ A reasonable task could be to store the points from the file as a matrix.  This can be done immediately, because the matrix constructor called with a list of values interprets each value as a matrix line:
-  open(INPUT, "< points.txt");
+  > open(INPUT, "< points.txt");
-  $matrix=new Matrix<Rational>(<INPUT>);
+  > $matrix=new Matrix<Rational>(<INPUT>);
-  close(INPUT);
+  > close(INPUT);