linetype corruption in ggplot2

Dear friends - another simple question: the assignment of linetype seems 
to be corrupted in the code below- I would want the solid line
to be the lowest? and also want the legend to be correct. I guess R 
orders the legend names alphabetically and could handle? that but
cannot unnderstand how the lines apparently are switched.

library(ggplot2)

BB <- cbind(c(1,2,3),c(2,4,6),c(3,6,9))
x <- c(2,3,4)
LT <- c("solid","dashed","dotted")

GG <- ggplot()
for (i in 1:3) {
 ? dd <- data.frame(x,BB=BB[i,],LT=LT[i])
 ? GG <- GG + geom_line(data=dd,aes(x=x,y=BB,linetype=LT),size=1)

}
GG+scale_y_continuous(breaks=seq(1,10))

I'm on Windows, R 4.0.5

All best wishes

Troels

Hello,

The problem is in the for loop. Every time through it the data 
argument changes and ggplot only evaluates when printing, not when 
it's constructing the object.

It's not a good idea to construct a ggplot object in a loop.

Why don't you put x and BB in a data.frame, reshape it to long format 
and plot all lines in the same instruction?


df1 <- data.frame(x, BB)
names(df1)[2:4] <- paste0("BB", 1:3)

df1_long <- reshape(
? df1, direction = "long",
? varying = names(df1)[2:4],
? v.names = "BB",
? timevar = "LT"
)
df1_long$LT <- LT[df1_long$LT]

ggplot(df1_long, aes(x, BB, linetype = LT)) +
? geom_line() +
? scale_linetype_manual(values = c(solid = "solid", dashed = "dashed", 
dotted = "dotted"))



Hope this helps,

Rui Barradas

?s 13:52 de 01/10/21, Troels Ring escreveu:

Dear friends - another simple question: the assignment of linetype 
seems to be corrupted in the code below- I would want the solid line
to be the lowest? and also want the legend to be correct. I guess R 
orders the legend names alphabetically and could handle that but
cannot unnderstand how the lines apparently are switched.

library(ggplot2)

BB <- cbind(c(1,2,3),c(2,4,6),c(3,6,9))
x <- c(2,3,4)
LT <- c("solid","dashed","dotted")

GG <- ggplot()
for (i in 1:3) {
?? dd <- data.frame(x,BB=BB[i,],LT=LT[i])
?? GG <- GG + geom_line(data=dd,aes(x=x,y=BB,linetype=LT),size=1)

}
GG+scale_y_continuous(breaks=seq(1,10))

I'm on Windows, R 4.0.5

All best wishes

Troels