Question

I am trying to create some functions that will avoid me to repeat plot options for different types of plot. I encounter some troubles as I try to create mechanisms to automatically handle Frameticks & Plot Range given the data considered within a given plot.

Module[{chartData},
        chartData = RandomInteger[20, 20];

BarChart[chartData,
                Frame -> {{True, True}, {True, True}},
                ImageSize -> 300,
                ChartStyle -> Black,
                FrameLabel -> {{"yName", None}, {None, "xName"}},
                ChartElementFunction -> "FadingRectangle",
                LabelStyle -> Directive[Black, Bold, 18],
                PlotRange -> {Automatic, 1.3*Max@chartData},
                FrameTicks -> {{{Round@Min@chartData, Round@(Max@chartData/2), 
                                Round@Max@chartData}, None}, 
                              {{0, Round@(Length@chartData/2), Length@chartData}, None}}
          ]]

Now Here is my attempt to simplify my life :

chartOptions[yName_, xName_] := {Frame -> {{True, True}, {True, True}},      
                                ImageSize -> 300,
                                ChartStyle -> Blue,
                                FrameLabel -> {{yName, None}, {None, xName}},
                                ChartElementFunction -> "FadingRectangle",
                                LabelStyle -> Directive[Black, Bold, 18],
                                FrameTicks -> {{{Round@Min@chartData, Round@(Max@chartData/2), 
                                                 Round@Max@chartData}, None}, 
                                              {{0,Round@(Length@chartData/2),     
                                               Length@chartData}, None}},
                                PlotRange -> {Automatic, 1.3*Max@chartData}}

This so that hopefully my actual Chart code is as such :

 Module[{chartData},
         chartData = RandomInteger[20, 20];

         BarChart[chartData,
         chartOptions["yName", "xName"]]]

But this does not work :

The idea is that the chartOptions function will be adjusted given the chart data of the actual plot where it is used.

I am now trying to only use things I trully understand so I hope such a problem does not require to much of your sophisticated skills 🙂 !

Answer 1

The problem is that in chartOptions the variable chartData is a free variable referring to a global definition. In the BarChart expression, the chartData variable is localized to the containing module and is thus invisible to chartOptions. Change chartOptions to accept chartData as a parameter:

chartOptions[chartData_, yName_, xName] := ...

and then adjust the BarChart expression accordingly:

Module[{chartData},chartData=RandomInteger[20,20];
  BarChart[chartData,chartOptions[chartData, "yName","xName"]]]