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find doesn't work with tables

Asked by Abdelmoumen Bacetti on 26 Mar 2017
Latest activity Commented on by Abdelmoumen Bacetti on 28 Mar 2017
hello
I'm trying to find the index vector of where appears a value in a one column of a table (not an array nor a cell).
However, "find" gives me the error shown on the snapshot.
Any ideas

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3 Answers

Guillaume
Answer by Guillaume
on 27 Mar 2017
 Accepted Answer

You would save yourself a lot of headache if you used the variable names instead of numerical indices for accessing the content of your tables:
big_table.UniqueWellID %instead of big_table{:, 1}
In any case, your main problem is that you want to compare char arrays, which you can't do with ==. Use strcmp to compare char arrays
find(strcmp(big_table.UniqueWellID, t1_u.UniqueWellID(1)))
%or if you really insist on using numerical indexing:
find(strcmp(big_table{:, 1}, t1_u{1, 1}))

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That was so precise and concise answer. Thank you so much.

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Answer by Peter Perkins
on 27 Mar 2017

find isn't going to work on a table, but it will work on the contents of a table. So Guillaume, is right that if you're looking for values in one variable, use dot subscripting.
Those strings, and the fact that you're searching for multiple hits for a single value, leads me to think you should be using categorical for the strings. And then when you get to the point when you need to find all the groups of rows in the table, not just one, you can easily use varfun or rowfun with that categorical as a grouping variable. Hard to give specific advice without knowing where you're headed.

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Answer by Walter Roberson
on 26 Mar 2017

If you are going to use variable number instead of variable name then you need to use {:,1} instead of (:,1)

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I've got the same thing.
indexes = find(big_table{:,1} == t1_u{1,1});

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