[R] custom function that plots other functions- problem

[Rui Barradas]

Hello,

Try the following. Note that argument 'how_many' is not needed, it can 
be derived from the length of the functions vector.



plotter<- function(f, range, quality){
     x <- seq(range[1], range[2], quality)
     y <- sapply(seq_along(f), function(.i) f[[.i]](x))
     plot(x, y[, 1])
     for(i in seq_along(f)[-1]){
     	lines(x, y[, i], col = i)  # argument 'col' added
     }
}

plotter(c(sin, cos), c(0,2*pi), .02)


Hope this helps,

Rui Barradas

Em 05-05-2013 15:16, Bartłomiej Drążczyk escreveu:
> Hi everyone!
>
> Could you please help me with the following assignment? My aim is to write
> a custom function that draws the plots of functions submitted by the user.
> The catch is, that we do not know the exact number of functions the user
> will select to draw.
>
> The program is relatively easy with one function, f.e sin:
>
> mf<- function(f,range,quality){
>
>                  x<- seq(range[1],range[2], quality);
>
>                  y<- f(x);
>
>                  plot(x,y);
> }
>
> mp(sin, c(0,2*pi), .02);
>
> but I encountered some problems while trying to provide more than one- the
> following structure generates mistakes:
>
> plotter<- function(f,howmany,range,quality){
>      x<-seq(range[1],range[2],quality)
>      y<- matrix(f,how_many)
>      plot(x,y[1,])
>      for(i in 2:how_many){
>      lines(x,y[i,])
>      }
> }
>
> plotter<-(c(sin(x),cos(x)),2,c(0,2*pi),.02)
>
> I would really appreciate your help with this program.
>
> Regards,
> Bartek
>
> 	[[alternative HTML version deleted]]
>
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