How to pop the content of a matrix in a way like pop the content of a cell

38 vues (au cours des 30 derniers jours)
raym
raym le 19 Juin 2020
Commenté : raym le 19 Juin 2020
We know that the arguments of a function can be placed in a cell and call it like this:
aCell = {arg1,arg2,arg3};
myFunction(aCell{:});
Is there a way to do this for a vector instead?
I tried this way, but it does not work
aVector = [2 3 4 5];
myFun(aVector(:)) % this does not work, the argument is a column vector [2;3;4;5] instead.
Similarly,
aVec = [1 2 3];
aCell = {'d','dew',aVec(:)} % I would expect aCell is {'d','dew',1,2,3}, but it is {'d','dew',[1;2;3]},
Thanks.
  2 commentaires
KSSV
KSSV le 19 Juin 2020
Try num2cell(aVec)
Stephen23
Stephen23 le 19 Juin 2020
Modifié(e) : Stephen23 le 19 Juin 2020
There is no way to do this with a numeric array (or a char array, logical array, etc.). The only ways to generate a comma-separated list (the proper name for what you are trying to do) are from a cell array or from a field of a structure:

Connectez-vous pour commenter.

Réponse acceptée

Ameer Hamza
Ameer Hamza le 19 Juin 2020
Madhan's answer already shows how to use num2cell. Following just show how can you avoid the creation of a temporary variable
v = [1 2 3];
myFun(struct('a', num2cell(v)).a)
  3 commentaires
Ameer Hamza
Ameer Hamza le 19 Juin 2020
Timing will be higher because of the additional overhead of struct creation (num2cell() being equivalent in both cases). However, it is only a concern if the function myFun() is itself has very small execution time (in order of microseconds) or the number of input arguments is in millions. If timing is a primary considerations, then it will be faster to just take input as an array rather than splitting it into an argument list. The point about obfuscation seems valid.
raym
raym le 19 Juin 2020
This is what I really want! Thanks!

Connectez-vous pour commenter.

Plus de réponses (2)

madhan ravi
madhan ravi le 19 Juin 2020
Modifié(e) : madhan ravi le 19 Juin 2020
aVector = [2 3 4 5];
aVector = num2cell(aVector);
myFun(aVector{:}) % ;)

Walter Roberson
Walter Roberson le 19 Juin 2020
No there is not.
You can num2cell the vector and assign that to a variable and do expansion on that.
There are ways to use auxiliary anonymous functions to do the num2cell for you, and even to do cell expansion on the result, but when you proceed that way, the MATLAB parser will not know that multiple outputs are required and will pull out only the first value.

Community Treasure Hunt

Find the treasures in MATLAB Central and discover how the community can help you!

Start Hunting!

Translated by