using word in a plot command

[Anglès d'Auriac]

Hello

I have a file 'tmptst('with two data-sets and the following script

cols = "red blue"
styles = "linesp linesp"
wids = "1 4"
plot for [i=1:2]  'tmptst' i i-1 lc rgb word(cols,i) lw word(wids,i) wi linesp ti sprintf("%d",i) # OK
plot for [i=1:2]  'tmptst' i i-1 lc rgb word(cols,i) lw word(wids,i) wi word(styles,i) ti sprintf("%d",i) # NON OK

the first plot (line 4) is fine (title, color, style and width) are OK,
but the second is not: " line 5: unrecognized plot type"
What is wrong on line 5 ?
Thank you

[Hans-Bernhard Broeker]

Your problem is that in line 5 you're trying to use the string not just as a parameter to some keyword, but as the keyword itself. The test case can be simplified to

gnuplot> plot sin(x) lc rgb "blue" lw "2" w "linesp"
                                                    ^
         unrecognized plot type

gnuplot> plot sin(x) lc rgb "blue" lw "2" w linesp   

[Anglès d'Auriac]

Thank you Hans-Bernhard Broeker for your explanation.
Indeed

a="linesp"
plot sin(x) lc rgb "blue" lw "2" w @a

works, but

plot sin(x) lc rgb "blue" lw "2" w @a

and

plot sin(x) lc rgb "blue" lw "2" w @word(a,1)
 plot sin(x) lc rgb "blue" lw "2" w sprintf("@%s",word(a,1))
 plot sin(x) lc rgb "blue" lw "2" w @sprintf("%s",word(a,1))

do not work.

So how can I switch between line, point and linesp in a plot for loop the choice between the 3 possibilities being determined by a string (like the colors eg) or possibly a function ?

[Anglès d'Auriac]

oh sorry for a misprint : the first not working line is

plot sin(x) lc rgb "blue" lw "2" w @"a"

[Anglès d'Auriac]

https://stackoverflow.com/questions/63689746/gnuplot-setting-line-style-in-a-for-loop
propose a solution using linespoints and a smart modification of the parameters.
It works with fine Version 5.0 patchlevel 0 last modified 2015-01-01
but not with Version 5.4 patchlevel 0 last modified 2020-07-13 (points never shown)