Is It Okay to Add Semicolons After Every Expression?

Take, for example, this piece of code which adds semicolons even when there is no output to suppress:

clear;
clc;

x = 1:10;
y = (x+1).^2;

plot(1,y(1),"r*");
hold on;

for idx = 2:10
    plot(idx,y(idx),"r*");
end
    
plot(x,y);

And this code which only includes semicolons when needed:

clear
clc

x = 1:10;
y = (x+1).^2;

plot(1,y(1),"r*")
hold on

for idx = 2:10
    plot(idx,y(idx),"r*")
end
    
plot(x,y)

(These are just examples.) Is adding semicolons to every expression (the first example) wrong in any way?

It's just that when not using the editor you are not told if there is output to suppress, so I thought it would just be easier to use semicolons everywhere instead of trying to remember or guess where they are needed. So is it syntactically/traditionally/etc wrong in any way?

Answer 1

[dpb]

Not "wrong", no. Superfluous in many instances, but not "wrong".

I think you'll find that with time in grade you'll begin to learn where they're needed and not and will gradually evolve to the less typing and clutter look. In the meantime, if you want to code that way and aren't bothered by the extra ones being in your m files to look at, "go for it!"

[Walter Roberson]

By the way:

If you have a function with no output arguments, or a function that tests nargout and does not assign outputs: then running the command by itself or running the command with semi-colon, does not make any difference.

testcmd

nargout = 0

testcmd;

nargout = 0

function varargout = testcmd
   fprintf('nargout = %d\n', nargout);
   if nargout > 0; varargout{1} = 'hello'; end
end

MATLAB does not interpret the testcmd; situation as indicating that one output is expected and that output is to be discarded: MATLAB interprets it as no output is asked for at all.

[dpb]

Yeah, all the semicolon does is suppress the command line echo if there is an output -- but that doesn't matter whether there is an output expected in the command or not. Without, it'll echo the variable name if there is a return variable or the default ans if there isn't.

[Alexander]

Ok, thank you!

[John D'Errico]

Be careful though, as the FDA (The Furry Dogs Association) has suggested there may be a link between excessive use of punctuation, expecially semi-colons, and cancer. It may in fact be valid, as a significant portion of the programmers who use semi-colons in excess will die of cancer, possibly within the next 50 years.