#213 Support Multiline Column and Row Labels for Matrices

[Artur Tarassow]

I am requesting an enhancement to allow for the display of multiline column and row labels when working with matrices.

Currently, gretl only displays the first 12 letters of any column and 20 letters of any row label. This can be problematic when working with longer descriptive labels, as the full context of the label is lost. Here an illustration of the current restriction:

matrix m = ones(1,1)
string label = "12345678901234567890"
cnameset(m, label)
rnameset(m, label)
print m

Here is an example output showing that some label gets cut:

       airco     prefarea        count  mean(price) mean(lotsize   min(price) min(lotsize)   max(price) max(lotsize) 
      0.0000       0.0000       298.00       56524.       4617.7       25000.       1650.0   1.4500e+05       16200. 
      0.0000       1.0000       75.000       73240.       5639.3       44555.       1950.0   1.7500e+05       12090. 
      1.0000       0.0000       120.00       80001.       5492.5       37900.       2175.0   1.7500e+05       15600. 
      1.0000       1.0000       53.000       99193.       6677.9       31900.       2275.0   1.9000e+05       13200. 

I propose adding the capability to support multiline labels that can be attached to the columns and possibly rows of a matrix. This would allow users to provide more detailed and informative labels, without being constrained by the character limit.

The benefits of this feature would be:

• Improved readability and understanding of matrix data, by providing more descriptive labels
• Make printing matrices less broad due to smaller ("stacked") column labels

How could that be implemented? Maybe its possible to make the newline operator, \n, available for string arrays:

strings labels = defarray("mean\n of some \n variable", "min", "max")

Best
Artur

[Allin Cottrell]

A couple of comments. On newlines in strings arrays, that's supported:

strings S = defarray(sprintf("line 1\nline 2"), "s2", "s3")

On supporting long column names in matrix printout, I'd say no. It's not at all clear what such a printout should look like. If I had to do this my inclination would be to label the columns as A, B, C, etc (or similar) and precede the actual matrix print with a key:

A = some relatively long description of the first column
B = some other long thing about the second
C = some even longer and fuller description pertaining to the third

and so on. Unless perhaps the matrix had very few columns and the strings were not all that long. Anyway, I can't see any one approach satisfying all customers, and it's easy enough to do this the way you want with hansl tools.

[Artur Tarassow]

Thanks for your comment(s), Allin.

A couple of comments. On newlines in strings arrays, that's supported:
strings S = defarray(sprintf("line 1\nline 2"), "s2", "s3")

Ah, that's good to know.

On supporting long column names in matrix printout, I'd say no. It's not at all clear what such a printout should look like.

Here is an example of what I have in mind. The labels for the columns 3 and 4 for comprise a single line break:

                 mean    mean
airco   count   price   lotsize
   0      298    68000   4512
   1      122    74000   3876

[Allin Cottrell]

OK, I see what you mean. That could work if each line of each label were reasonably short.

[Sven Schreiber]

We discussed this some more, and a problem there is the fact that adding newline characters into the labels mixes up the content and the (intended) formatting. The newlines would have unintended side effects when you want to extract or work with the labels afterwards in some other way.
What @atecon wants to achieve, apparently, is to be able to pretty-print the matrix along with its labels. So the idea is that "somebody" can write a hansl function (possibly in the extra addon) that does that. Of course it's going to be a bit tedious to get the formatting right, but the same caveat applies to the requested fully native implementation.

[Artur Tarassow]

Thanks for the summary. It's a pity that newlines have such side-effects.

Ok, maybe I can come up with some function candidate to realize this request in near future. I think, this ticket can be closed now.

[Sven Schreiber]

OK, I'm closing this as suggest by Artur.