Re: Plot Table of functions does not distinguish colors

*To*: mathgroup at smc.vnet.net*Subject*: [mg102689] Re: Plot Table of functions does not distinguish colors*From*: Bill Rowe <readnews at sbcglobal.net>*Date*: Wed, 19 Aug 2009 07:01:25 -0400 (EDT)

On 8/18/09 at 6:09 AM, fdimer at gmail.com (fd) wrote: >All, this seems like a simple question, but when I want to create a >table with different function as in the example >Plot[Table[Sin[n x], {n, 1, 3, 1}], {x, 0, 2 Pi}, PlotRange -> All, >PlotStyle -> Thick] >I get all three plots with the same color. If I instead write the >table manually >Plot[{Sin[x], Sin[2 x], Sin[3 x]}, {x, 0, 2 Pi},PlotStyle->Thick] >This gives a different plot with a different color for each plot. >Can anyone shed some light on why this behavior? This is due to the way in which Plot evaluates its arguments. It substitutes a numerical value for the dependent variable into the expression to be plotted then evaluates the expression. When you give Plot an expression that evaluates to a list of values, Plot sees this as a single multi-valued function and plots it in one color. If you give Plot an explicit list, Plot sees that list as several functions and plots each in a separate color. So, to get an expression that generates a list of values to plot in several colors, you need to force evaluation of the expression before Plot starts doing its thing, You can do this with Evaluate. That is: Plot[Evaluate@Table[Sin[n x], {n, 1, 3, 1}], {x, 0, 2 Pi}, PlotRange -> All, PlotStyle -> Thick] will result in a Plot with each curve plotted in a separate color.