Re: Options in ListPlot and Plot
- To: mathgroup at smc.vnet.net
- Subject: [mg38621] Re: Options in ListPlot and Plot
- From: "Allan Hayes" <hay at haystack.demon.co.uk>
- Date: Wed, 1 Jan 2003 03:39:49 -0500 (EST)
- References: <aur8vq$8gn$1@smc.vnet.net>
- Sender: owner-wri-mathgroup at wolfram.com
Mike, Plot has the attribute HoldAll and checks the form of input before any evaluation. Your problem has nothing to do with putting the options into a list. Example: opts = Frame -> True; rng = {x, 0, 5}; expr = x^2; Plot[expr, rng, Evaluate[opts]]; Plot[expr, Evaluate[rng], opts]; Plot[expr, Evaluate[rng], Evaluate[opts]]; A commonly observe consequence is to do with mulitiple plots. Here Plot needs to know that it will be getting a list of formulas to plot. expr2 = {x,x^2}; Plot[expr2,{x,0,5}, Frame->True]; Plot[Evaluate[expr2],{x,0,5}, Frame->True]; "Mike" <mikeh1980 at optusnet.com.au> wrote in message news:aur8vq$8gn$1 at smc.vnet.net... > For appearance reasons I usually place all my Plot and ListPlot options in a > list eg. > > optionA={PlotStyle->{....},Frame->True, and so on} > > When I plot a list everything is fine: > > ListPlot[list, optionA] > > out=> nice plot > > but when I use options in Plot I get an error message unless I wrap Evaluate > around the options. > > For example > > Plot[x^2,{x,0,5}, optionB] > > out=> messages > > Plot[x^2,{x,0,5}, Evaluate[optionB]] > > out=> nice plot > > > ??? why is this so???? > > Why must I wrap Evaluate around my options in Plot? > > thanks > > Mike > > ps. This is with version 4.0.2 on a G4 power Mac. > >