Colours plot vector based - r

Question

I have a vector z like this
z <- as.numeric(as.factor(c("A","B","C","D","E","F","G","H")))
and for different days a data frame df like this
df[[1]]
ID LON LAT
A 1 1
B 10 14
C 12 13
df[[2]]
ID LON LAT
A 2 3
B 11 18
D 12 13
df[[3]]
ID LON LAT
A 13 1
E 10 14
D 12 13
where the IDs are the ones in z but can be different for every day.
I have assigned a colour to each element of the vector
range01 <- function(x)(x-min(x))/diff(range(x))
rainbow(7)
cRamp <- function(x){
cols <- colorRamp(rainbow(7))(range01(x))
apply(cols, 1, function(xt)rgb(xt[1], xt[2], xt[3], maxColorValue=255))
}
and what I would like to do is to plot for every day my df with the colours cRamp(z) but I am no able to link the ID value in every df with the one in z
Here is my code
for (i in 1:length(myfiles)){
plot(df[[i]]$LON,df[[i]]$LAT, col = cRamp(z))
map(add=T,col="saddlebrown",interior = FALSE)
legend("topleft", legend=c(unique(df[[i]]$ID)), col=cRamp(z))
}
but the colour for e.g. ID A are not the same for every day!
Many thanks

Answer 1

Maybe something like this:
z <- LETTERS[1:7]
df <- list(
data.frame(ID=LETTERS[1:3],
LON=c(1,10,12),
LAT=c(1,14,13)),
data.frame(ID=LETTERS[3:5],
LON=c(2,11,18),
LAT=c(2,9,20))
)
layout(t(1:2))
for (i in 1:2){
plot(df[[i]]$LON, df[[i]]$LAT,
col = rainbow(length(z))[match(df[[i]]$ID,z)],
pch=16)
legend("topleft",
legend=z,
col=rainbow(length(z)),
pch=16)
}