MATLAB Answers

set order of elseif

85 views (last 30 days)
Rub Ron
Rub Ron on 17 Dec 2020
Commented: James Tursa on 17 Dec 2020
Updated.
I have this code structure inside a loop. x, y and z are 1/0 variables. In this case the order of the elseif statement is: first x is evaluated, then y then z
if x
%code for case x
elseif y
%code for case y
elseif z
%code for case z
end
I would like to define a varible order (for the previous case order={'caseX','caseY','caseZ'}), where I can change the order in which the elseif statement is evaluated. So if I set order={'caseZ','caseX','caseY'}, I should get this: (first z is evaluated, then x then y)
order={'caseZ','caseX','caseY'}
%%% then
if z
%code for case z
elseif x
%code for case x
elseif y
%code for case y
end
An hint will be appreciated.

  2 Comments

Ive J
Ive J on 17 Dec 2020
I'm not sure if I understood you correctly, but seems easier if you use switch/case. See here:
KSSV
KSSV on 17 Dec 2020
Have a look on switch.

Sign in to comment.

Accepted Answer

James Tursa
James Tursa on 17 Dec 2020
Edited: James Tursa on 17 Dec 2020
Does this do what you want:
order = [1 2 3]; % or whatever
for k=1:numel(order)
switch order(k)
case 1
if( x )
% code for case x
break;
end
case 2
if( y )
% code for case y
break;
end
case 3
if( z )
% code for case z
break;
end
end
Or if you prefer the case selection could be for characters 'x', 'y', and 'z' instead of numbers 1, 2, 3.
The key is to have those break statements inside the cases so that the if-elseif-elseif control structure is emulated properly.

  9 Comments

Show 6 older comments
Bruno Luong
Bruno Luong on 17 Dec 2020
I like the combo solution.
Rub Ron
Rub Ron on 17 Dec 2020
Thanks Bruno, I wish I can accept both answers at the same time, with only one click
James Tursa
James Tursa on 17 Dec 2020
I gave Bruno a vote since he contributed a key part of the solution.

Sign in to comment.

More Answers (2)

Bruno Luong
Bruno Luong on 17 Dec 2020
prefered_order = 'xzy';
b = [x y z]; % logical conditions (in if/elseif)
code_to_be_exec = { @xcode, @ycode, @zcode }; % code in the if elseif block put in functions
[~,i] = ismember(prefered_order, 'xyz');
j = find(b(i), 1, 'first');
if ~isempty(j)
feval(code_to_be_exec{i(j)});
end

  2 Comments

Rub Ron
Rub Ron on 17 Dec 2020
do you think there is a way to preseve the if elseif structure? for easy-to-read purpose.
Bruno Luong
Bruno Luong on 17 Dec 2020
Of course, unroll all 6 possible permutations
if strcmp(prefered_order, 'xyz')
% your original if/else
elseif strcmp(prefered_order, 'yxz')
% another order...
elseif strcmp(prefered_order, 'zyx')
....
end

Sign in to comment.


KSSV
KSSV on 17 Dec 2020
Are you looking something like this.
if z
%code for case z
order = ['case','z'] ;
elseif x
%code for case x
order = ['case','x'] ;
elseif y
%code for case y
order = ['case','y'] ;
end

  3 Comments

Rub Ron
Rub Ron on 17 Dec 2020
Hi, no. What I want is to chance the order of the if else if statement, base on a variable order that indicates which order should be considered. Is it clear what I am trying to achieved?
KSSV
KSSV on 17 Dec 2020
order = 'z'
if strcmpi(order,'z')
%code for case z
order = ['case','z'] ;
elseif strcmpi(order,'x')
%code for case x
order = ['case','x'] ;
elseif strcmpi(order,'y')
%code for case y
order = ['case','y'] ;
end
Also have a look on switch.
Rub Ron
Rub Ron on 17 Dec 2020
I updated my post, hopefully now it is clearer.

Sign in to comment.

Community Treasure Hunt

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

Start Hunting!

Translated by