Update a value in a struct in another function
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I have a struct which is initialized by this:
function myStruct = defult_config
myStruct.myLenth = 1;
end
myStruct.myLength = 1 is an initial value and it needs to be updated by another fuction, myUpdate:
function out = myUpdate(myStruct)
myStruct.myLength = 2;
out = [];
end
However, myUpdate doesn't update myStruct and myStruct.myLength is still shown 1.
Any way to update a value in a struct by another function?
采纳的回答
dpb
2024-6-20
Variables in functions are local to the function and you don't return the struct; in fact in myUpdate you don't return anything at all...
function myStruct = myUpdate(myStruct)
myStruct.myLength = 2;
end
You would have to use this in some context like
workingStruct=default_config;
... % whatever else
workingStruct=myUpdate(workingStruct);
... % more stuff...
This is going to be an awkward use pattern one imagines and unless there's a lot more than shown going on, simply writing
workingStruct=default_config;
... % whatever else
workingStruct.myLength=newvalue;
... % more stuff...
inline will probably be as legible code and easier...because unless the update value is a constant as shown, you're not providing it in the updating function and if you have to also add it as the second argument, then may as well just go ahead and update the struct itself directly.
Now, if there are some 20 other values as well, then mayhaps some similar structure may be desireable.
更多回答（1 个）
You must return the modified myStruct from myUpdate():
myStruct.myLength = 1
myStruct = myUpdate(myStruct)
function myStruct = myUpdate(myStruct)
myStruct.myLength = 2;
end
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