I've used _ and __ as placeholders for missing or invalid data. I then filter them out as needed in calculations. It's simple and has worked out fine for me.
On Wed, Sep 20, 2017 at 11:22 AM, Erling Hellenäs <[email protected]> wrote: > Hi all! > > Programs which acted on arrays containing missing data would need > definitions which accounted for this missing data. Take a look at R. I > think most languages have ways of handling missing data, even if > calculations do not always work directly on arrays containing missing data, > like they do in R. > > We could possibly have arrays of floats containing missing data without > being able to do all our calculations on these arrays? We already have > arrays of floats containing NaN, infinity and negative infinity? Would it > be possible to have some of these NaN floats signal missing data? Could > arrays with such NaN floats be used in some calculations which accounted > for this missing data? > > Typically when you create report programs, you take care of missing data? > The user might fill a form, he does not answer to some questions, the mean > value of an answer for all users is the mean of the values filled, but how > many and how big percentage are not filled is an important part of the > result? > > Cheers, > > Erling > > > Den 2017-09-20 kl. 16:40, skrev Henry Rich: > >> If a list (a) can contain 'missing' entries, what does (# a) mean? What >> happens to >> >> mean =: +/ % # >> >> ? >> >> How is u/\. a defined? >> >> Henry Rich >> >> On Wed, Sep 20, 2017 at 10:25 AM, Erling Hellenäs < >> [email protected]> >> wrote: >> >> Because you possibly have an array where some cells have missing data and >>> you want to run your functions directly against this array without caring >>> about the possibly missing data. Thats how I think R works. All functions >>> work with cells where the data is missing. Correct me if I'm wrong. R >>> might >>> become the mostly used tool for statistics any day. It might well be >>> worth >>> the effort to look at their solutions if you ask me. /Erling >>> >>> Den 2017-09-20 kl. 12:27, skrev Raul Miller: >>> >>> Why not just use another number? Many more bits that way... >>>> >>>> Thanks, >>>> >>>> >>>> ---------------------------------------------------------------------- >>> For information about J forums see http://www.jsoftware.com/forums.htm >>> >> ---------------------------------------------------------------------- >> For information about J forums see http://www.jsoftware.com/forums.htm >> > > ---------------------------------------------------------------------- > For information about J forums see http://www.jsoftware.com/forums.htm > ---------------------------------------------------------------------- For information about J forums see http://www.jsoftware.com/forums.htm
