For and if in gnuplot

Question

I have a little problem, I need to join the for loop with the if condition to graph different functions quickly, here I leave the prototype code

reset
set terminal png
plot for [i=1:2]\
    set output "Graph".i.".png"\
    if (i==1)\
        x title 'Graph'.i;\
    if (i==2)\
        2x+3x**2 title 'Graph'.i;\
    if (i==3)\
        3x+8+4x**2-15x**3 title 'Graph'.i
unset output 

Answer 1

I am not sure if you are looking for something like the following example. If not, please rephrase your question. You could for example define several functions and select them by the ternary operator (check help ternary). In a for loop you can also define items as strings. This allows you to change the numerical order as you like.

Script:

### select function to plot via number
reset session

f1(x) = x
f2(x) = 2*x + 3*x**2
f3(x) = 3*x +8 +4*x**2 - 15*x**3
f4(x) = x**2
f5(x) = x**3

myFunction(n) = n==1 ? f1(x) : n==2 ? f2(x) : n==3 ? f3(x) : n==4 ? f4(x) : n==5 ? f5(x) : NaN

set xrange[-1:1]

plot for [n in '1 2 5 4'] '+' u (x):(myFunction(n)) w l ti sprintf("Graph %s",n)
### end of script

Result: