MATLAB: Basic Question: How to index into table by a text column

extract data from tables

Hello, new to Matlab. I have a table imported into Matlab. How to I extract all data in all columns from that table in only the rows labelled "hardness"? I do know that I can't extract from a table (at least I think I can't). I was able to convert the table to a cell array but I am still unable to figure out how to get just the rows with the text label "hardness" out of this table.

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Presuming you used the names when creating the table, index by the desired name values--

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MATLAB: How to pre-allocate table rows

Danial, I interpret your question as

"I have a table with one row. I'd need the same table, but lengthened to 10 rows so that I can fill in rows 2-9 without growing it one row at a time."

This actually isn't specific to table, although the fact that tables can hold heterogeneous types makes it a bit more interesting.

(By the way, good on you for knowing to start with {'a'}, and not just 'a'.)

One option is to simply repmat the one-row table to be 10 rows:

>> t = table({'a'},1)
t = 
    Var1    Var2
    ____    ____
    'a'     1   
>> t = repmat(t,10,1)
t = 
    Var1    Var2
    ____    ____
    'a'     1   
    'a'     1   
    'a'     1   
    'a'     1   
    'a'     1   
    'a'     1   
    'a'     1   
    'a'     1   
    'a'     1   
    'a'     1

If you're filling in the table, it doesn't much matter what's in rows 2-9, since you'll be overwriting them. But if you're a stickler, you can assign to the 11'th row, then delete it:

>> t = table({'a'},1);
>> t(11,:) = t(1,:);
>> t(11,:) = []
t = 
    Var1    Var2
    ____    ____
    'a'     1   
    []      0   
    []      0   
    []      0   
    []      0   
    []      0   
    []      0   
    []      0   
    []      0   
    []      0

Hope this helps.

MATLAB: Subtracting column values in Matlab tables

YourTable{:,2} - YourTable{:,3}

assuming that they are the same data type.

(EDIT: corrected a minor typo in the first term)

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MATLAB: How to pre-allocate table rows

MATLAB: Subtracting column values in Matlab tables

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