matlab equivalent of "+="

Hello all,

First of all, I would like to say thanks for all your help. Your prompt and accurate replies save me a lot of programming time.

When I used to program in java, there was a useful command, so to say:

"counter+="

which will increment the variable itself. This was a useful function to use in for loops. I was wondering if matlab had a shortcut expression such as this, something that I can use in an array even, so like

somearray[i]+=; can work? Or is the only available option to say counter=counter+1? I just want to see if there was a faster way to write the expression.

thanks!

Sam

Answer 1

[Sean de Wolski]

for-loops automatically increment and any reassignment inside the loop will be reset at the next increment:

for ii = 1:10
  disp(ii)
  ii = 5000;  
end

To be able to toy with the counter use a while loop and to the assignment manually

count = count+1;

[Samuel]

okay, so the count=count+1 is the only way to increment it?

I will wait and see if i see other answers, and if not, I will accept your answer. Thanks!

[Jan]

@Samuel: count=count+1 *is* the only straight method. It is efficient in Matlab.

[Pierre]

It is not efficient, especially when "count" is a variable like

   mycountcell{individual,session,variable}(1:end-1,:,:,1)

but it's the only method Matlab knows.

[Luca Amerio]

Completely agree with Pierre. When "count" is a long string, this gets very confusing.

[Adam]

It's annoying to type, but why is it 'not efficient'?

[Ilya Gurin]

It's annoying both to type and to read.

Answer 2

[Walter Roberson]

MATLAB does not have ++ or += or -- or -= or *= or /= or %= and is not expected to get any of those for some time (if at all.)

I think if you look back at your Java you will find it was ++ rather than += that you were using for incrementing.

[Walter Roberson]

MATLAB's parser is hand-crafted rather than table driven or generated out of something like BNF, which makes it sometimes fragile for adding new operators.

In the last decade or so, MATLAB has added only two new operators:

• the ~ operator for input and output arguments to indicate that the corresponding value is unused or to be discarded. That was, IIRC, R2009a.
• The " operator for string data type, in R2017a, after introducing the data type in R2016b. It took them until R2019b to get in into the rest of the language. I am not sure that Simulink has fully caught up yet.

Syntax changes for non-operators has been more rapid; in particular there have been changes in class definitions. But they are very conservative about new operators.

[Alexandre Sagona]

1000€ to not have all operators other langages have. Love to use sprintf also

[Andrew]

@Alexandre Sagona Strong agree; I wish my MATLAB class at uni would just let me use C instead.

[Real User]

data(complex_index_sequence, another_one) = data(complex_index_sequence, another_one) + data2

would benefit from "+=". It would be much easier to read and maintain.

It helps a bit to define the indices separately before that line, but "+=" would be better.