Rename Struct Fields Old Function

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Hello,
I have a struct that has 20 different field names. Somewhere within these 20 names, it has a field name of B_in_ which I want to rename to B_m because I converted its value from inches to meters. I have found this function renameStructField, but it requires a scalar structure for the renaming. I tried this:
a="B_in_"
b="B_m"
FullTable=renameStructField(FullTable,a,b)
Interestingly if I were to do isscalar(a), and isscalar(b) they both return 1 which means they are both scalars. However, it still throws the scalar structure error.
Anyone know why this does not work, and how to make it work?
Thank you,
Luck
  6 Comments
Stephen23
Stephen23 on 8 Jun 2022
So far no one has mentioned the role of data design: this question is a good illustration of why forcing meta-data into fieldnames (or even worse, variable names) makes it harder to process that data. For a detailed explanation:
Better data design relies on understanding that meta-data is data, and data is best stored in a variable, not in its name:
S.B_val = 3.4;
S.B_unit = 'in';
Note how much easier this is to work with, compared to fiddling around with fieldnames.
Luck Haviland
Luck Haviland on 8 Jun 2022
Hi Stephen23,
You have a wise point. However, I imported this data from an excel sheet where each header was prenamed with the unit of the dimension, as the data was from measuring via electronic micrometer the dimensions of individual specimens to be tested in shear.
Since the data was imported like this, I think it is difficult for me to rearrange it in a good data design way.
Thank you,
Luck

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Accepted Answer

Jonas
Jonas on 8 Jun 2022
the question is not if your fieldnames are scalar but if the struct is scalar. you will not have any problems if the atruct has multiple fields but is one dimensional:
myStructScalar.inIn=5;
renameStructField(myStructScalar,'inIn','inM')
but if your struct is not scalar, this will not work directly
myStruct(1).inIn=2
myStruct(2).inIn=6
renameStructField(myStruct,'inIn','inM')
jowever you can vreate a new field and do the conversion in the same step and remove the old field afterwards
for structNr=1:numel(myStruct)
myStruct(structNr).inM=myStruct(structNr).inIn;
end
rmfield(myStruct,'inIn')
  1 Comment
Luck Haviland
Luck Haviland on 8 Jun 2022
That is unfortunate and I am very sad. Thank you for the answer Jonas.

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More Answers (1)

Jan
Jan on 8 Jun 2022
Edited: Jan on 8 Jun 2022
Try this C-Mex verions:
An M-version is included also. I'm updating the M-version to accept string currently. It is coming in a few days.

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