asMatrix¶

Purpose¶

Strips metadata from dataframe and returns matrix.

Format¶

x_mat = asMatrix(x_meta)¶

Parameters:	x_meta (NxK matrix or dataframe.) – data.
Returns:	x_mat (NxK matrix) – data matrix.

Examples¶

// Load data
fname = getGAUSSHome() $+ "examples/yarn.xlsx";
yarn = loadd(fname, "cat(yarn_length) + cat(amplitude) + cat(load) + cycles");

// Strip metadata from 'yarn' to return a matrix
yarn_mat = asMatrix(yarn);

After the above code, the first five rows of yarn are equal to:

yarn_length     amplitude        load     cycles
        low           low         low        674
        low           low         med        370
        low           low        high        292
        low           med         low        338
        low           med         med        266

while the first five rows of yarn_mat are equal to:

           1           1        674
           1           2        370
           1           0        292
           2           1        338
           2           2        266

The matrix does not have variable (column names) and the string category labels have been replaced by the integer key values for the labels in the original dataframe.

Remarks¶

Date variables will be in Posix time (seconds since Jan 1, 1970).
Categorical and string variables will be returned as the integer keys for the corresponding category.
Numeric variables will be unchanged.
Variable names will be removed.