17.2.2 Pretty Table Printing

In order to pretty print the table, one uses the options associated with the PRETTY as specified in the syntax above. Since pretty printing can only be done with one property, the PROPERTY option must be specified if the table has more than one property. The table printing can be done in four different ways depending on the appearance of BYRES and TAGVAL in the command line. Let us consider the case when neither option is specified.

If we had an arbitrarily wide piece of paper, a readable way of outputting all the data in a table would be to have one column for every tag in the table, one row for every residues' data, and a page for every segment. Each data point would be output under its tag, and it would be easy to see how a particular type of data varied from one residue to the next.

However, we do not have infinitely wide paper. We can accommodate this shortcoming by taking advantage of the fact that some tags appear very frequently. The program selects those tags which appear most frequently and uses these to be the headers of the columns. As each residue's data is printed, the program checks to see if any of the data's tags are the same as any of the headers. If they are, the data is printed in that column. Any data which is not printed in these columns is printed at the right of the page in tag-value format. Tag-value format means that for each data point, the tag is printed alongside the data so that one can see what the numbers stand for.

The TAGVAL option specifies that the entire table is to be printed in tag value format. No selection of column headers is made. The BYRES option causes the residues to be collected into groups of the same name and printed in alphabetical order of the residues. The selection of headers is done on the frequency of tags within each groups rather than with the entire segment. As a result, using the BYRES option will increase the amount of data printed in columns. BYRES and TAGVAL may both be specified which means that the collection of data by residue still occurs, but the data is output using tag value format.

The CUTOFF option is used to mask out numbers whose magnitude is small. When a cutoff is specified and the magnitude of a data point in a column is smaller than the magnitude of the cutoff, an M is printed in place of the number. If a data point is to be printed in tag value format and its magnitude is smaller than the cutoff's magnitude, the tag value pair is not printed at all.