# Is there a way to extract the name of a field of a struct as string

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Omer Yasin Birey on 15 Feb 2019
Commented: Stephen Cobeldick on 15 Feb 2019
Hi all, lets say I have this struct 'str50' and this struct consists of 3 fields and their names are V10, V100, V1000. I want to extract the name of the field as string. I tried inputname() but it didn't work
inputname(str50.V10)
So I want to get the output as below
ans =
V10
Thank you!

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Omer Yasin Birey on 15 Feb 2019
Unfortunately, fieldnames doesn't work if I call the field as well, it extracts all the fields if I type
fieldnames(str50)
madhan ravi on 15 Feb 2019
I am not certain what you want , perhaps
str50.('V10') %?
Stephen Cobeldick on 15 Feb 2019
"Is there a way to extract the name of a field of a struct as string"
Yes, using fieldnames. But your example shows some confusion about the topic: although you ask in your title how to extract the fieldname of a structure, the syntax S.F refers to the contents of structure S's field F, i.e. another array (which may or may not be an unrelated structure) but that other array certainly not the same thing as S, so it does not know anything about the fieldnames of S.
It is as if you put an array into a cell, then take it out of the cell and want the array to somehow "know" that it had just been stored in a cell array. MATLAB does not store such information.

Stephan on 15 Feb 2019
Edited: Stephan on 15 Feb 2019
Hi,
the following gives a string array with the fieldnames of the struct:
A.a123 = 1
A.bbb = 2
B = string(fieldnames(A))
pick the needed field by indexing it or by logical indexing:
C = B(2)
D = B(B=="bbb")
or use:
B = fieldnames(A)
C = string(B{2})
Best regards
Stephan