[R] linetype corruption in ggplot2

[Troels Ring]

Thanks a lot, Rui - this works well - although I still fail to see why a 
loop could not do it although your explanation for the problem is well 
taken!

All best
Troels

Den 01-10-2021 kl. 15:21 skrev 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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>
> ______________________________________________
> R-help using r-project.org mailing list -- To UNSUBSCRIBE and more, see
> https://stat.ethz.ch/mailman/listinfo/r-help
> PLEASE do read the posting guide 
> http://www.R-project.org/posting-guide.html
> and provide commented, minimal, self-contained, reproducible code.