Removing rows of table based on logical array

Hello, I have an imported table of data that is 122 x 11.

I have identified an xdata and ydata I want to use, and have named them such.

ydata comes from column 7 of my table.

I am singling out the heighest 10 values in this column by using

topTenData = maxk(ydata, 10)

that identified a minimum value of 1.01, and I'm uninterested in any data below that value.

I am attempting to get rid of all rows that are smaller than this using (remember column 7 is ydata):

TT = data(:,7) < 1.01
data(TT,:) = []

What I expect to happen is anywhere in which TT returns true, the row will be removed.

Instead, I get an error stating:" A table row subscript must be a numeric array containing real positive integers, a logical array, a character vector, a string-array, a cell array of character vectors, or a pattern scalar."

Does this mean that if my raw data rows have a multitude of different types of data within each column, it is not possible to delete the rows this way? If so, can I get some guidance on a better method? Thanks!

Answer 1

[Voss]

I think the problem is with this line:

TT = data(:,7) < 1.01

With data being a table, I get the error, "Undefined operator '<' for input arguments of type 'table'."

Instead of using parentheses ( ) you should use curly braces { } to access the contents of a table, as in:

TT = data{:,7} < 1.01

Then that line will run and TT will be a logical vector you can use to delete rows from the table as you intend.

Here's a simple complete example to illustrate:

% a table with two columns:
data = table(randi(10,10,1),randi(10,10,1))

data = 10×2 table
    Var1    Var2
    ____    ____

      8       7 
      9       6 
      5       4 
      1       2 
      6      10 
      1       6 
      7       3 
      4      10 
      3       6 
     10       2 

% a logical vector saying whether the data in column 2 is less than 4.
% Note: use curly braces {} to access the contents of a table.
TT = data{:,2} < 4

TT = 10×1 logical array
   0
   0
   0
   1
   0
   0
   1
   0
   0
   1

% remove those rows from the table:
data(TT,:) = []

data = 7×2 table
    Var1    Var2
    ____    ____

     8        7 
     9        6 
     5        4 
     6       10 
     1        6 
     4       10 
     3        6 

[Nicholas]

Thanks!

[Peter Perkins]

Voss is correct up to a point, but there is some late-breaking R2023a news that changes the story. Please see my comment in another thread:

https://www.mathworks.com/matlabcentral/answers/1986959-splitting-table-based-on-one-column-value#comment_2818633