How can I have a function that has a string as the input.

I am trying to make a function that requires you to input the name of a color to get the output. My code, for example, is:

function [] = displayColor(color)

    if color == 'black'
      disp('black line');
      plot(x.^2);
  elseif color == 'blue'
      disp('blue line');
      plot(x.^3);
  end

When I do this, I get the error:

Error using  == 
Matrix dimensions must agree.

Error in displayColor (line 4)
if color == 'black'

How do I fix this so I can input a string as the function variable??

[Stephen23]

Do NOT use == to check if character vectors are the same. Use strcmp or strcmpi.

Answer 1

[David Fletcher]

You need to use strcmp(string1,string2) to compare as the size of the color variable might be a different length to whatever fixed length string you are trying to equate it with (which is why you are getting the error).

[Walter Roberson]

Note that you would not get this error if you really did have a string as an input. But you do not: instead you have a character vector as input. You need strcmp() or strcmpi() to compare character vectors.

[spete]

Hi I am still confused. So if I put in displayColor(black), I then add strcmp(black) before the code of the function?

[Walter Roberson]

if strcmp(color, 'black')

The input to the function would be like displayColor('black')