gnuplot title variables separated by text

Question

I am trying to add text+variable+text+variable into the title of the plot in gnuplot batch file.

I have variables lines and last containing numbers(1 and 350) and the code Ive got is:

set title sprintf("Secondary structure CA IX residues".first,"to".lines) 

It prints: "Secondary structure CA IX1".

Can anyone help how to write this correctly, so that it will write Secondary structure CA IX residues 1 to 350 with gaps?

Answer 1

You have two options:

1. Use the . operator to concatenate your variables into strings:

   set title "Secondary structure CA IX residues " . first . " to " . lines
   

   I have added in spaces between the " and . for clarity, these will not be featured in the output. You are responsible for adding in the appropriate spaces in the string sections.

2. Use sprintf as it was intended:

   set title sprintf("Secondary structure CA IX residues %d to %d", first, lines)
   

   The first argument to sprintf is a format string, which should not contain any variables. Placeholders (such as %d) are used to indicate the positions that variables should be inserted. Subsequent arguments to the function are the variables to be inserted. As your two variables appear to be integers, %d is the appropriate format specifier to use.

Answer 2

If you need spaces, insert them!

first = 1
lines = 350
set title sprintf("Secondary structure CA IX residues %d to %d", first, lines)