functions take preference to assignin/evalin variables
3 vues (au cours des 30 derniers jours)
Afficher commentaires plus anciens
po,gpo,eoeo
le 9 Juin 2020
Modifié(e) : Stephen23
le 9 Juin 2020
Can someone explain to me why the code below outputs 'test from function', indicating that the function takes preference to a variable assigned by assignin to the parent function scope? This just seems like a bug to me.......
function display_weirdness()
assign_weird();
disp(test)
end
function assign_weird
assignin('caller','test','test')
end
function t=test
t='test from function';
end
1 commentaire
Stephen23
le 9 Juin 2020
Modifié(e) : Stephen23
le 9 Juin 2020
"...indicating that the function takes preference to a variable assigned by assignin to the parent function scope?"
Yes.
For good reason: because that is more efficient for the JIT engine. If the JIT engine always had to keep looking for magically created variables (e.g. that shadow functions, as your example does) and then when it finds them it would have to replace whatever it had already compiled with something entirely new and compile everything again, then clearly this would slow things down considerably.
This topic has been discussed plenty of times before:
Summary: passing data using the recommended methods is more efficient and less buggy than magically creating variables.
Réponse acceptée
Ameer Hamza
le 9 Juin 2020
Modifié(e) : Ameer Hamza
le 9 Juin 2020
Yes, this is an inconsistent behavior similar to this question: https://www.mathworks.com/matlabcentral/answers/10727-bug-regarding-precedence-of-variables-over-functions-sharing-the-same-name, but it is not considered a bug, as explained by Walter's answer here: https://www.mathworks.com/matlabcentral/answers/10727-bug-regarding-precedence-of-variables-over-functions-sharing-the-same-name#answer_15521. It is a consequence of JIT. Following will work correctly
function display_weirdness()
test = '';
assign_weird();
disp(test)
end
0 commentaires
Plus de réponses (0)
Voir également
Catégories
En savoir plus sur MATLAB Compiler dans Help Center et File Exchange
Community Treasure Hunt
Find the treasures in MATLAB Central and discover how the community can help you!
Start Hunting!