How to check whether a column exist in a table?

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

[Carlos Aguilar]

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);

Answer 1

[KSSV]

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

[Alon Rozen]

Thanks a lot KSSV - you are a treasure :)

Pity that there is no simple, one command, way to do that. I think MathWorks should consider to add something like 'isfield' for that purpose.

Thanks again,

Alon

[KSSV]

There might be other ways ..will let you know..

[Armand Mensen]

any(strcmp('My Column', My_Table.Properties.VariableNames))

[Nicolas Petit]

ismember('My Column', My_Table.Properties.VariableNames)

[Gabriel Blanco]

Bonjour Nic!

[Nikolaus Koopmann]

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

Answer 2

[jkr]

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

returns 1 if found, 0 if not

[AusPollen]

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]

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

Answer 3

[Sean Lynch]

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

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

[Nikolaus Koopmann]

no ismember is slow