[R] Mixing lty specifications in legend

[Duncan Murdoch]

On 07/11/2007 7:01 PM, Peter Dunn wrote:
> Hi all
> 
> I have a plot with lines, one specified as (say) lty=1, 
> using standard line types, and another as (say) my
> own spec: lty="51".
> 
> I can't get  legend  to display both.  Toy example:
> 
> 
>> plot(1~1)
>> legend("topright", lty=c("51",1), legend=c("My own","Standard"))
> Error in segments(x1, y1, x2, y2, ...) : invalid line type: must be
> length 2, 4, 6 or 8
> 
> 
> Any ideas?

Fairly kludgy idea:  plot it twice, once for each style.  For example,

plot(1 ~ 1)
legend("topright", lty=c("55",NA_character_), legend=c("My own","Standard"))
legend("topright", lty=c(0,1), legend=c("My own","Standard"))

The man page says the NA is not allowed, but it does appear to work. 
Perhaps there's another way to get blanks using the manual spec.

Duncan Murdoch