I want to create a new column with words that are atributed regarding the numerical values of another column. How can I proceed?

I have a column with "consumption" and values range between 3000 and 8000.

From 3000 to 4000, I want "low" in the new column; From 4000 to 7000, I want "medium"; From 7000 to 8000, I want "high".

How can I create this new column?

Answer 1

[Walter Roberson]

It is not possible to put a string into a numeric matrix. You will need to use a table() or a cell array.

NewColumn = repmat( {''}, length(consumption), 1);
mask = consumption >= 3000 & consumption <= 4000;
NewColumn(mask) = cellfun(@(S) [S, 'low'], NewColumn(mask), 'Uniform', 0);
mask = consumption >= 4000 & consumption <= 7000;
NewColumn(mask) = cellfun(@(S) [S, 'medium'], NewColumn(mask), 'Uniform', 0);
mask = consumption >= 7000 & consumption <= 8000;
NewColumn(mask) = cellfun(@(S) [S, 'high'], NewColumn(mask), 'Uniform', 0);

The code would be considerably simpler if your ranges did not overlap -- you have defined 4000 as belonging to both low and medium, and you have defined 7000 as belonging to both medium and high.

[Eduardo Rocha]

Of course I don't want to overlap the ranges.. Thank you very much, it worked perfectly :)

[Walter Roberson]

I will have to guess about which way you want the overlap to be resolved.

NewColumn = cell( length(consumption), 1 );
NewColumn(consumption < 3000) = {'Forest Fire'};
NewColumn(consumption >= 3000 & consumption < 4000) = {'low'};
NewColumn(consumption >= 4000 & consumption < 7000) = {'medium'};
NewColumn(consumption >= 7000 & consumption < 8000) = {'high'};
NewColumn(consumption >= 8000) = {'Forest Fire'};

Only you can prevent Forest Fires.