programming - Call Functions From File Without Modifying Context (Sandbox)

Let's say I have file named test.m containing

test[arg1_] := ( Print[arg1];)

What is the best technique for calling test like test["value"] while preventing test from being added to the $ContextPath?

The following almost works except you must know function values ahead of time

Block[{$ContextPath,test}, Needs["test`"];test["test"]];

My question is: How do I generalize the call above to work with any number of functions without the user needing to input definitions manually?

Answer

As Nasser notes in a comment every Symbol has a context. You should be aware that Symbols are created during parsing. See: Local variables in Module leak into the Global context.

Alright, now that we worked out what you want here is the simplified answer:

We can perform a similar operation to BeginPackage with Block:

Block[{$ContextPath = {"runPrv`", "System`"}, $Context = "runPrv`"}, . . .]

We can combine this with Leonid's method from Is it possible to use Begin and End inside a Manipulate? to keep contexts from being fully resolved until we are ready for evaluation inside the Block. (Note that Global` Symbols are still created, as discussed above, but they will not be defined.) I believe "runPrv`" may be left out of $ContextPath in our application so long as we don't change the $Context from "runPrv`" within the Block itself. Finally we have:

SetAttributes[runPrivate, HoldAllComplete];

runPrivate[code_] :=
  With[{body = MakeBoxes @ code},
    Block[{$ContextPath = {"System`"}, $Context = "runPrv`"},
      ToExpression @ body]]

Now:

runPrivate[

  Get["test.m"];
  a = 5;
  test[a]
]

5

Global Symbols a and test remain undefined:

?a

?test

Global`a

Global`test

Comments

plotting - Filling between two spheres in SphericalPlot3D

Manipulate[ SphericalPlot3D[{1, 2 - n}, {θ, 0, Pi}, {ϕ, 0, 1.5 Pi}, Mesh -> None, PlotPoints -> 15, PlotRange -> {-2.2, 2.2}], {n, 0, 1}] I cant' seem to be able to make a filling between two spheres. I've already tried the obvious Filling -> {1 -> {2}} but Mathematica doesn't seem to like that option. Is there any easy way around this or ... Answer There is no built-in filling in SphericalPlot3D . One option is to use ParametricPlot3D to draw the surfaces between the two shells: Manipulate[ Show[SphericalPlot3D[{1, 2 - n}, {θ, 0, Pi}, {ϕ, 0, 1.5 Pi}, PlotPoints -> 15, PlotRange -> {-2.2, 2.2}], ParametricPlot3D[{ r {Sin[t] Cos[1.5 Pi], Sin[t] Sin[1.5 Pi], Cos[t]}, r {Sin[t] Cos[0 Pi], Sin[t] Sin[0 Pi], Cos[t]}}, {r, 1, 2 - n}, {t, 0, Pi}, PlotStyle -> Yellow, Mesh -> {2, 15}]], {n, 0, 1}]

plotting - Plot 4D data with color as 4th dimension

I have a list of 4D data (x position, y position, amplitude, wavelength). I want to plot x, y, and amplitude on a 3D plot and have the color of the points correspond to the wavelength. I have seen many examples using functions to define color but my wavelength cannot be expressed by an analytic function. Is there a simple way to do this? Answer Here a another possible way to visualize 4D data: data = Flatten[Table[{x, y, x^2 + y^2, Sin[x - y]}, {x, -Pi, Pi,Pi/10}, {y,-Pi,Pi, Pi/10}], 1]; You can use the function Point along with VertexColors . Now the points are places using the first three elements and the color is determined by the fourth. In this case I used Hue, but you can use whatever you prefer. Graphics3D[ Point[data[[All, 1 ;; 3]], VertexColors -> Hue /@ data[[All, 4]]], Axes -> True, BoxRatios -> {1, 1, 1/GoldenRatio}]

plotting - Mathematica: 3D plot based on combined 2D graphs

I have several sigmoidal fits to 3 different datasets, with mean fit predictions plus the 95% confidence limits (not symmetrical around the mean) and the actual data. I would now like to show these different 2D plots projected in 3D as in but then using proper perspective. In the link here they give some solutions to combine the plots using isometric perspective, but I would like to use proper 3 point perspective. Any thoughts? Also any way to show the mean points per time point for each series plus or minus the standard error on the mean would be cool too, either using points+vertical bars, or using spheres plus tubes. Below are some test data and the fit function I am using. Note that I am working on a logit(proportion) scale and that the final vertical scale is Log10(percentage). (* some test data *) data = Table[Null, {i, 4}]; data[[1]] = {{1, -5.8}, {2, -5.4}, {3, -0.8}, {4, -0.2}, {5, 4.6}, {1, -6.4}, {2, -5.6}, {3, -0.7}, {4, 0.04}, {5, 1.0}, {1, -6.8}, {2, -4.7}, {3, -1.

Blog

Search This Blog