How to check whether a column exist in a table?

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Alon Rozen 2016-11-24

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https://ww2.mathworks.cn/matlabcentral/answers/313776-how-to-check-whether-a-column-exist-in-a-table

评论： Nikolaus Koopmann 2024-7-2

采纳的回答： KSSV

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Hi all,

I search for this question in the web and found the following solution: Suppose I have a table named 'My_Table' and want to check if it contains a column (field) named 'My_Column'. The code:

Exist_Column = strmatch('My_Column',My_Table.Properties.VariableNames)

should result in logical that answer the question. I checked it and it works. However, the Matlab editor commented that 'strmatch' is not a recommended function to use because it is about to be removed in future version and suggest instead the use of either 'strncmp' or 'validatestring'. Problem is that both do not return a logical and more steps are required to get the answer.

So, my question is: what is the simplest recommended way to determine if a certain column name exist in a table?

Thanks,

Alon

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Carlos Aguilar 2017-12-31

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Just came across to this question. An anonymous function will also do the job (and will be reusable within the scope):

isTableCol = @(t, thisCol) ismember(thisCol, t.Properties.VariableNames);

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KSSV 2016-11-24

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在 MATLAB Online 中打开

Exist_Column = strcmp('My_Column',My_Table.Properties.VariableNames)
val = Exist_Column(Exist_Column==1) ;

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Gabriel Blanco 2019-6-25

Bonjour Nic!

Nikolaus Koopmann 2022-11-29

在 MATLAB Online 中打开

any("MyColumn" == string(My_Table.Properties.VariableNames))

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更多回答（2 个）

jkr 2019-5-14

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sum(ismember(mx.Properties.VariableNames,'NameYouWantToCheck'))

returns 1 if found, 0 if not

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AusPollen 2021-5-23

Nice! although you don't need to sum if you switch the ismember arguments, ie. use ismember('My_Column',My_Table.Properties.VariableNames)

Nachiket Wadwankar 2024-2-9

This is exactly what I wanted. Thanks a lot for this trick!!

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Sean Lynch 2021-9-5

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https://ww2.mathworks.cn/matlabcentral/answers/313776-how-to-check-whether-a-column-exist-in-a-table#answer_781079

I used "any", but agree "ismember" is even better

exists = any(strcmp('Column-Name', My_Table.Properties.VariableNames))