Arjen Markus (11 february 2003) I had a question from a customer about numbers that were displayed with too many digits, like "28.000" instead of "28.0". So, this raised the question: what can we do to make the appearance of (floating-point) numbers more elegant?
As it turns out, the format command has a lot of options, one of them is the # attribute to %g. Now, if all you have is the textual description of the effects, you will be very puzzled indeed.
So, here is a little script that examines the effects:
# Check the effects of the various formats for floating-point numbers
#
foreach value {1.0 -1.0 1.01 -1.01 0.00001 -0.00001 1000000.0 -1000000.0} {
set result ""
foreach form {%g %-g %6g %6.4g %#.4g %06g %-6g} {
append result [format " >$form<" $value]
}
puts "Value $value: $result"
}I have reformatted the output a bit, to get the following table:
Formats: %g %-g %6g %6.4g %#.4g %06g %-6g Value 1.0: >1< >1< > 1< > 1< >1.000< >000001< >1 < Value -1.0: >-1< >-1< > -1< > -1< >-1.000< >-00001< >-1 < Value 1.01: >1.01< >1.01< > 1.01< > 1.01< >1.010< >001.01< >1.01 < Value -1.01: >-1.01< >-1.01< > -1.01< > -1.01< >-1.010< >-01.01< >-1.01 < Value 0.00001: >1e-05< >1e-05< > 1e-05< > 1e-05< >1.000e-05< >01e-05< >1e-05 < Value -0.00001: >-1e-05< >-1e-05< >-1e-05< >-1e-05< >-1.000e-05< >-1e-05< >-1e-05< Value 1000000.0: >1e+06< >1e+06< > 1e+06< > 1e+06< >1.000e+06< >01e+06< >1e-06 < Value -1000000.0: >-1e+06< >-1e+06< >-1e+06< >-1e+06< >-1.000e+06< >-1e+06< >-1e+06<