How do I comment out a large block of code in MATLAB?

I want to do this in an easy way.

[Carol Hurwitz]

CTRL+R

[Hamid Nourani]

Great

[Md.Al AMIN TALUKDER]

ctrl+r

u can use both for single or multiple line.

Answer 1

[Doug Hull]

To comment out a large block of code in the Editor or Live Editor, select the code and on the "Editor" or "Live Editor" tab, click the "Comment" button. This inserts a "%" symbol in front of each selected line. Alternatively, select the code and type "Ctrl" + "R". To uncomment the selected text, click the "Uncomment" button or type "Ctrl" + "Shift" + “R”.  

On macOS systems, use “Command” + “/” to comment and “Command” + “Option” + “/” to uncomment. On Linux® systems, use “Ctrl” +”/” to comment and “Ctrl” + “Shift” + “/” to uncomment. 

You also can use the block comment operators "%{" and "%}". The "%{" and "%}" operators must appear alone on the lines that immediately precede and follow the block of help text. For example: 

%{ 

     code to be commented out 

%} 

For more information, see https://www.mathworks.com/help/matlab/matlab_prog/comments.html 

[James Tursa]

Also, the control-r and control-t work for C source code as well ... putting and removing the // style comments.

[Kesam reddy Dhaneswara reddy]

Tq sir

[Jake Zivontsis]

THIS METHOD NO LONGER WORKS IN MATLAB 2020

%{

...

%}

it appears there is no way to block comment in MATLAB 2020. You MUST line comment every single line.

Very interesting way to downgrade for the new version.....

[Steven Lord]

That functionality is still present in releases R2020a, R2020b, and R2021a. It is possible that something about your file or how you're writing these comment delimiters is preventing them from being interpreted as block comments. For instance, %{ and %} must appear alone on a line.

x = 1

x = 1

%{ start of block comment?
y = 2

y = 2

%}
z = 3

z = 3

%{
w = 4
v = 5
%}

Because of the text following the %{ before "y = 2" it is a regular comment, not a block comment. So we execute the line that creates the y variable.

Because there is no %{ associated with the %} before "z = 3" it too is a regular comment and the z variable is created.

The %{ and %} surrounding the lines defining the w and v do comprise a block comment, so those variables are not created.

whos

  Name      Size            Bytes  Class     Attributes

  x         1x1                 8  double              
  y         1x1                 8  double              
  z         1x1                 8  double              

Can you show us a small code segment where you see %{ and %} not functioning as block comments?

[Shapol Mohamed]

In Matlab 2020, you have to use ctrl+/ (cmd+/ for mac) to comment a block and to uncomment you have to use ctrl+t (cmd+t for mac).

Answer 2

[CHUANQIANG ZHANG]

Ctrl + R comment selected lines. Ctrl + T uncomment select lines.

https://stackoverflow.com/questions/30925796/is-there-a-shortcut-key-to-comment-multiple-lines-in-matlab-editor/30926004#30926004

[Sainyam Gupta]

you are making us fool bc

ctrl+t open new tab.....mf

[Manik Sharma]

Ctrl+t opens new tab bc.

[Steven Lord]

Search the list of keyboard shortcuts for the word "comment" or for the key combination Ctrl+T and you should see the actions associated with commenting out code or that will be performed in various components of the MATLAB Desktop in the keyboard shortcut set you've told MATLAB to use.

In my MATLAB installation using the Windows keyboard shortcut set, Ctrl+T creates a new tab in the Help Browser but uncomments code when used in the Editor.

Answer 3

[Wesam Rezk]

Simply start with *... and write whatever you want. This will enable you to write a very long comment line

For example *... This is a very very long comment

Answer 4

[Wick]

Rather than comment large sections of code, I bypass them with the following syntax.

for dont_go_here = []
  % code I want to skip including all nested comments, etc. can stay here unmolested
end

This assumes that your if, for, case, try, and switch commands within that block are all terminated properly with an 'end' Otherwise the script won't parse.

[THONTI BEERAIAH]

Thank you, this is what I need.