dfname#

Purpose#

Set column variable names.

Format#

x_meta = dfname(x, varnames[, columns])#

Parameters:

X (NxK matrix or dataframe) – data.
varnames (Mx1 vector) – Names to apply to columns specified in columns.
columns (Mx1 vector) – Optional argument, indices of columns in X to be assigned names. Default = all columns.

Returns:

x_meta (NxK dataframe) – Data with column names in varnames assigned to the columns in columns.

Examples#

Example 1: Convert a matrix to a dataframe and set variable names#

x = { 1  15  15,
      5  19   8,
     16  14   4,
      7  19   6 };

// Create new dataframe x_meta with the specified variable names
df_x = dfname(x, "Planes"$|"Trains"$|"Automobiles");

print df_x;

The above code will print out:

Planes  Trains  Automobiles
    15           15
    19            8
    14            4
    19            6

Below we change the name of an existing variable.

// Change variable name of first column of x_meta
df_x = dfname(df_x, "Airplanes", "Planes");

Airplanes  Trains  Automobiles
        1      15           15
        5      19            8
       16      14            4
        7      19            6

Example 2: Convert a string array to a dataframe and set variable names#

// Create a 3x1 string array
apples = "Gala" $| "Fuji" $| "Rome";

// Create new dataframe
apples = dfname(apples, "Variety");
print apples;

The above code will print out:

Variety
   Gala
   Fuji
   Rome

Now that apples is a dataframe, we can use the concatenation operators to combine it with a numeric variable.

// Create a 3x1 vector
n = { 437, 672, 231 };

// Add a name to 'n' and combine with 'apples'
apples = apples ~ dfname(n, "count");
print apples;

Variety    count
   Gala      437
   Fuji      672
   Rome      231

Remarks#

dfname() will automatically convert string arrays to categorical variables matrices to datframes with numeric columns.
To convert date strings to date variables, use asDate().
asdf() will also convert strings and numeric data to dataframes with the option to set the variable names.