Explicitly numbered string?

Hi,

How do I explicitly define a string with numbering? Look at the example below. Suppose "numbers" are unknown and I want to name the figures Q1, Q2 etc.

numbers=3;
fname={'Q1' 'Q2' 'Q3'};
for i=1:numbers
  if i==1
      x = -2*pi:0.01:2*pi;
  elseif i==2
      x = -3*pi:0.01:3*pi;
  else
      x = -4*pi:0.01:4*pi;
  end
  y = sin(x);
  h=figure
  plot(x,y);
  print(h,'-dpng',fname{1,i});
end

Answer 1

[Guillaume]

My recommendation is to use sprintf which lets you compose any arbitrary string that you want.

fnames = cell(1, numbers);
for i = 1:numbers
  fname{i} = sprintf('Q%d', i);
end

Or as a one-liner:

fnames = cellfun(@(n) sprintf('Q%d', n), 1:numbers, 'UniformOutput', false);

Note that the format string of sprintf is very flexible. If you had more than 10 numbers and wanted to generate: Q01, Q02, ..., Q10, etc.:

sprintf('Q%02d', i)

[Jan]

Unfortunately undocumented yet:

fnames = sprintfc('Q%d', 1:numbers)

[nilsotto]

Many thanks guys!

Answer 2

[Azzi Abdelmalek]

numbers=3;
fname=genvarname(repmat({'Q'},1,numbers),'Q')
for ii=1:numbers
  x = -(ii+1)*pi:0.01:(ii+1)*pi;
  y = sin(x);
  h=figure
  plot(x,y);
  print(h,'-dpng',fname{ii});
end

[Guillaume]

While genvarname would work in this case, it's not for generating abritrary strings, only valid variable names. The set of valid filenames is much greater than the set of valid variable names.