#2259 summation of strings

[Daniel Molina García]

Maybe it is not a bug, but I don't see a reason why the following code should not output 2.0. Tested in gnuplot 5.2.8.

gnuplot> a="1"
gnuplot> print sum [i = 1:2] a
         warning: encountered a string when expecting a number
         Did you try to generate a file name using dummy variable x or y?

[Ethan Merritt]

The error message seems clear enough. "sum" wants numerical values to sum, not strings.
Compare
print sum [i=1:2] int(a)
or
print sum [i=1:2] real(a)

[Daniel Molina García]

Yes, I understand the error. My concern is because the following two options work.

gnuplot> a="1"
gnuplot> print a+a
2
gnuplot> sum = 0.0
gnuplot> do for [i=1:2] {
more> sum = sum + a
more> }
gnuplot> print sum
2.0

I am not used to gnuplot developer ideas, but I would expect sum to support strings which contain numbers.