[R] help with sapply, plot, lines

[Uzuner, Tolga]

Hi,

I am trying to plot multiple lines on a graph.

The function is particularly simple:

sigma<-function(lambda) atm-2*rr*(lambda-0.5)+16*str*(lambda-0.5)^2

which uses the variables atm, rr and str...

I define these as such:

atm<-0.4
rr<-0.2
str<-0.1


and this plots fine:

plot(seq(0.01,0.99,0.01),sigma(seq(0.01,0.99,0.01)),ylim=c(0,1))

Now, I want to plot the same function for different values of str, as follows:

sapply(seq(0,0.3,0.05),function(s) {str<-s; lines(seq(0.01,0.99,0.01),sigma(seq(0.01,0.99,0.01)))})

Hoping that sigma will lexically scope into str and that lines will appear on the same plot as the one I first drew above.

Instead, I just get this:
> sapply(seq(0,0.3,0.05),function(s) {str<-s; lines(seq(0.01,0.99,0.01),sigma(seq(0.01,0.99,0.01)))})
[[1]]
NULL

[[2]]
NULL

[[3]]
NULL

[[4]]
NULL

[[5]]
NULL

[[6]]
NULL

[[7]]
NULL

and the plot does not change.

Any assistance appreciated.

Regards,
Tolga








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