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2

equivalent of isfield for tables

I'd like to know if my Matlab table has a particular column. If it was a structure I'd use isfield. Is there a built in function for this?

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2 Answers

Answer by Georges-Andre Chaudron on 19 Jan 2017
 Accepted Answer

I would also like to suggest using ismember()
For instance:
f1 = 1; f2 = 10; t = table(f1,f2)
t =
f1 f2
__ __
1 10
ismember('f1', t.Properties.VariableNames)
logical
1
It also works for a range of values:
ismember({'f0','f1','f2'}, t.Properties.VariableNames)
1×3 logical array
0 1 1

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Answer by Roger Parkyn on 15 Sep 2015
Edited by Roger Parkyn on 15 Sep 2015

This issue was also raised by Pawel Kusmierek ( 123242-why-isfield-does-not-work-with-tables-but-fieldnames-does ). He gave a reasonably tidy work-around, in short:
name_exists = any(strcmp('Var_Name',fieldnames(Table_Name)))

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Note that fieldnames returns all object properties, which for a table includes both variable names and the Properties structure. To get just the column/variable names, query the VariableNames property:
t = table({'one';'two'}, [1;2])
t =
Var1 Var2
_____ ____
'one' 1
'two' 2
>> t.Properties.VariableNames
ans =
'Var1' 'Var2'
>> fieldnames(t)
ans =
'Var1'
'Var2'
'Properties'

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