How to input legend in figure with one variable?

Question

I have a variable x, whose value is

x=0:3:30;

I want to input a legend as

My code is like

x = 0:3:30;
figure(1); hold on; grid on;
for i=1:length(Var)
    plot(f1(val(x)));
end
legend('input 0', 'input 3', ..........)
figure(2); hold on; grid on;
for i=1:length(Var)
    plot(f2(val(x)));
end
legend('input 0', 'input 3', ..........)
figure(3); hold on; grid on;
for i=1:length(Var)
    plot(f3(val(x)));
end
legend('input 0', 'input 3', ..........)

Is there any method to input legend easily?

When I change x, I have to change all lenged inputs... its so bad... :(

Answer 1

You can create a cell array of strings, and pass that to legend. I just came up with this bit of code to generate your legend strings. It looks a little clunky, but it works.

s = split(sprintf('input %d\n',x'),char(10));
legend(s{1:end-1})

sprintf applies the formatter 'input %d\n' to each value in x. That creates a string with legend entries separated by newlines ('\n' equal to char(10)). split splits the string at the newlines. But because the string ends with a newline, split creates an empty string as the last element of the output. s is a cell array:

s =
  12×1 cell array
    'input 0'
    'input 3'
    'input 6'
    'input 9'
    'input 12'
    'input 15'
    'input 18'
    'input 21'
    'input 24'
    'input 27'
    'input 30'
    ''

s{1:end-1} returns all strings but the last one.