[R] linetype corruption in ggplot2

[Rui Barradas]

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

Às 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
> 
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