Creating Objects

*To*: mathgroup at smc.vnet.net*Subject*: [mg122287] Creating Objects*From*: Gabriel Landi <gtlandi at gmail.com>*Date*: Sun, 23 Oct 2011 06:25:39 -0400 (EDT)*Delivered-to*: l-mathgroup@mail-archive0.wolfram.com

Dear MathGroup (and perhaps some Wolfram employees), Does anyone know how to create Objects in Mathematica, such as those produced by LinearModelFit or NDSolve`ProcessEquations? For instance, let data be a set of statistical data. Then data["Mean"] would give me the mean, data["Values"] would return me the original values, etc. Here is an example from LinearModelFit: data = {{0, 1}, {1, 0}, {3, 2}, {5, 4}}; lm = LinearModelFit[data, x, x]; Save["Model.txt",lm]; The saved output is lm = FittedModel[{"Linear", {0.18644067796610198, 0.6949152542372881}, {{x}, {1, x}}, {0, 0}}, {{1., 1., 1., 1.}}, {{0, 1}, {1, 0}, {3, 2}, {5, 4}}, {{1., 0.}, {1., 1.}, {1., 3.}, {1., 5.}}, Function[Null, Internal`LocalizedBlock[{x}, #1], {HoldAll}]] Which has, basically, only the data and the fitted parameters. Nonetheless, by doing lm["FitResiduals"] it computes the residuals for me. In my impression, this is as close as one can get to object-oriented programming in Mathematica, and would be a quite useful feature to use. I haven't found any documentation on this. Anyone knowns? Sincerely, Gabriel Landi

**Follow-Ups**:**Re: Creating Objects***From:*DrMajorBob <btreat1@austin.rr.com>