Add Fields to an existing Structure
272 Ansichten (letzte 30 Tage)
Ältere Kommentare anzeigen
Paul Mitchell
am 11 Jun. 2022
Kommentiert: Stephen23
am 24 Dez. 2023
Hi,
I have structure, for example
S.Level0=0
I have a field structure I want to add to S namely
S.Level1.SubLevel0.SubLevel1.SubLevel2.Text = '1234';
where i have the above fields defined in a cell array
f = {'SubLevel0','SubLevel1','SubLevel2','Text'}
and the string cvar='1234' being the required value
is there an elegant way to produce
S.Level1.SubLevel0.SubLevel1.SubLevel2.Text='1234'
using f & cvar ?
Thank You
0 Kommentare
Akzeptierte Antwort
Paul
am 11 Jun. 2022
S.Level0=0;
f = {'SubLevel0','SubLevel1','SubLevel2','Text'};
cvar = '1234';
S = setfield(S,'Level1',f{:},cvar);
S.Level0
S.Level1.SubLevel0.SubLevel1.SubLevel2.Text
4 Kommentare
Paul
am 11 Jun. 2022
I don't know where the OP is going with this and so don't have a position on whether or not it's the right way to go. Just trying to answer the question. Having said that, getfield() can be used in a similar fashion to extract based on f.
S.Level0=0;
f = {'SubLevel0','SubLevel1','SubLevel2','Text'};
cvar = '1234';
S = setfield(S,'Level1',f{:},cvar);
plot(rand(3))
title(getfield(S.Level1,f{:}))
Weitere Antworten (2)
Image Analyst
am 11 Jun. 2022
Having field names that are unknown in advance, and their names are only determined by getting their name from a cell array variable sounds like a bad idea. It's probably one of the worst and most common ideas and it comes up every week.
However it is possible to do bad things in MATLAB and the FAQ will show you how to do it and explain why it's bad.
I'm sure Stephen will also chime in with additional reasons why you really don't want to do this even though you think you do.
2 Kommentare
Image Analyst
am 12 Jun. 2022
The solution you accepted will do what you want but as you can see, to get this unknown field name you have to do some pretty cryptic stuff that makes the code almost unmaintainable. Would be better to use fixed and known names rather than dynamically varying names, as I hope someday you realize. But good luck with it. You might also like to read the FAQ:
And Stephen's tutorial:
Dror Liran
am 20 Dez. 2023
Bearbeitet: Dror Liran
am 24 Dez. 2023
What you are after is called dynamic field names, the matlab documatation is here: https://www.mathworks.com/help/matlab/matlab_prog/generate-field-names-from-variables.html
Anyway the way to do it is something like:
names = ["name1" "name2"];
a.fld1 = 1;
a.fld2 = "a";
a.(names(1)) = "whatever";
3 Kommentare
Stephen23
am 24 Dez. 2023
"I have tried it and it works for me on matlab 2023b"
It should work in R2023b, dynamic fieldnames were added more than twenty years ago in R13:
Siehe auch
Kategorien
Mehr zu Startup and Shutdown finden Sie in Help Center und File Exchange
Community Treasure Hunt
Find the treasures in MATLAB Central and discover how the community can help you!
Start Hunting!