dtDayofWeek#

Purpose#

Extracts the day of the week component from a date/time variable as a decimal number. Default is to start on Sunday (0-6).

Format#

dow = dtDayofWeek(X[, column, start_Monday])#

Parameters:

X (TxK dataframe) – Data with metadata.
column (Scalar or string) – Optional, name or index of the date variable in X to get days of the week from. Default = first column.
start_Monday (Scalar) – Optional, indicator variable to start week on Monday (1-7).

Returns:

dow (Tx1 vector) – The day of the week the dates in the column specified by column.

Examples#

First find the day of the week components using a Sunday start.

// Load data
fname = getGAUSSHome("examples/yellowstone.csv");
data = loadd(fname);

// Get quarters for date column
dow = dtDayofWeek(data, "Date");

// Print first and last five dates
head(data[., "Date"]);
tail(data[., "Date"]);

// Print corresponding days of week
"Day of Week (Sunday start):"
head(dow);
tail(dow);

The code above prints the following table, with days ranging from 0-7:

          Date
    2016/01/01
    2015/01/01
    2014/01/01
    2013/01/01
    2012/01/01

          Date
    1990/12/01
    1989/12/01
    1988/12/01
    1987/12/01
    1986/12/01

   Day of Week
(Sunday Start):
              5
              4
              3
              2
              0

              6
              5
              4
              2
              1

Now, find the day of the week using a Monday start:

 // Get day of the week for date column
dow = dtDayofWeek(data, "Date", 1);

// Print corresponding days of the week
"Day of Week (Monday start):"
head(dow);
tail(dow);

     Day of Week
(Monday Start):

              5
              4
              3
              2
              7

              6
              5
              4
              2
              1