Importing data: recognizing if a variable is present

If I import data into matlab, how can I make it look for a specific variable? In the files attached, if z is present, then I'll do whatever calculations later in the code, and the same for a. I'm just a loss looking for a way to make matlab look for these variables. Is there a way to say to matlab, 'if a is present, then do some calculation' and vice versa for z?

Answer 1

[SRT HellKitty]

You can read about the Exist Command here.

For your example, you can do the following;

if exist('z','var') == 1
  %Do z calculation
end
if exist('a','var') == 1
  %Do a Calculations
end

Answer 2

[Guillaume]

If you use readtable to import your csv files, matlab will automatically recognise that there is a header and use the names in that header as variable names of your table (as long as these names make valid variable names). It is trivial to check if a variable is present in a table:

t = readtable('ex1.csv');

if ismember('z', t.Properties.VariableNames)
   %z is a variable
   plot3(t.x, t.y, t.z);
else
   %z is not present
  plot(t.x, t.y);
end