MATLAB: How do we do operations directly on table elements in matlab

table

I am thinking of doing min max normalization of my data where if x is vector the procedure is as follows x = (x- min(x))/(max(x)-min(x)). However I want to do this operation directly on the table elements which have 150 rows and 42 features and I want to normalize each of these columns. Is there any one line procedure to do it without using for loop or something like that ? I know we could use curly and dot bracket indexing but the result is not gonna be a table though.

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normalized_data = normalize(data, 'range'); %works on a table, normalizes to [0 1]

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MATLAB: Existing table, populate a column with string (receiving errors)

You are close, but you are trying to assign a character vector to a double variable (NaN = not a number). You can see that if you run the command summary(mytable).

You also do not need to put the text into a cell if you use the string data type.

See if you can get this code to work for your needs.

myArray = nan(5,2)
mytable = array2table(myArray);
mytable.Properties.VariableNames = {'colA', 'colB'};
mytable2 = convertvars(mytable,"colB",'string');
mytable2.colA(:) = 459;
mytable2.colB(:) = "words"

You say you have a lot of data. If the variables already exist, you could do something like this:

colA = nan(5,1);
colB = strings(5,1);
mytable = table(colA,colB);
mytable.colA(:) = 459; % just a random number, proof-of-concept that it works
mytable.colB(:) = "words" % this throws errors

MATLAB: Loop for finding a threshold and change corresponding number

As per my comment to the question, the loop you've shown is unnecessary:

aa = (data - min(data, [], 2)) ./ (max(data, [], 2) - min(data, [], 2));  %in R2016b

I'm assuming that you want to find where aa first crosses the threshold for each row. If not, see ImageAnalyst's answer.

[r, c] = find(aa >= 0.76)
crossthreshold = accumarray(r, c, [size(aa, 1), 1], @min)

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MATLAB: Existing table, populate a column with string (receiving errors)

MATLAB: Loop for finding a threshold and change corresponding number

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