This part of the tutorial assumes that you know how to use MATLAB and are familiar with MATLAB structures. The terminology is similar to that of a MATLAB structure. The financial time series object term component is interchangeable with the MATLAB structure term field.
A financial time series object always contains three component
desc (description field),
indicator field), and
dates (date vector). If you
build the object using the constructor
the default value for the description field is
a blank character vector (
''). If you build the
object from a text data file using
the default is the name of the text data file. The default for the
frequency indicator field is
Objects created from operations can default the setting to
For example, if you decide to pick out values selectively from an
object, the frequency of the new object might not be the same as that
of the object from which it came.
The date vector
dates does not have a default set
of values. When you create an object, you have to supply the date
vector. You can change the date vector afterward but, at object creation
time, you must provide a set of dates.
The final component of a financial time series object is one
or more data series vectors. If you do not supply a name for the data series,
the default name is
series1. If you have multiple
data series in an object and do not supply the names, the default
is the name series followed by a number, for example,
Here is an exercise on how to extract data from a financial time series object. As mentioned before, you can think of the object as a MATLAB structure. Highlight each line in the exercise in the MATLAB Help browser, press the right mouse button, and select Evaluate Selection to execute it.
To begin, create a financial time series object called
dates = (datenum('05/11/99'):datenum('05/11/99')+100)'; data_series1 = exp(randn(1, 101))'; data_series2 = exp(randn(1, 101))'; data = [data_series1 data_series2]; myfts = fints(dates, data);
myfts object looks like this:
myfts = desc: (none) freq: Unknown (0) 'dates: (101)' 'series1: (101)' 'series2: (101)' '11-May-1999' [ 2.8108] [ 0.9323] '12-May-1999' [ 0.2454] [ 0.5608] '13-May-1999' [ 0.3568] [ 1.5989] '14-May-1999' [ 0.5255] [ 3.6682] '15-May-1999' [ 1.1862] [ 5.1284] '16-May-1999' [ 3.8376] [ 0.4952] '17-May-1999' [ 6.9329] [ 2.2417] '18-May-1999' [ 2.0987] [ 0.3579] '19-May-1999' [ 2.2524] [ 3.6492] '20-May-1999' [ 0.8669] [ 1.0150] '21-May-1999' [ 0.9050] [ 1.2445] '22-May-1999' [ 0.4493] [ 5.5466] '23-May-1999' [ 1.6376] [ 0.1251] '24-May-1999' [ 3.4472] [ 1.1195] '25-May-1999' [ 3.6545] [ 0.3374]...
There are more dates in the object; only the first few lines are shown here.
The actual data in your
Now create another object with only the values for
srs2 = myfts.series2
srs2 = desc: (none) freq: Unknown (0) 'dates: (101)' 'series2: (101)' '11-May-1999' [ 0.9323] '12-May-1999' [ 0.5608] '13-May-1999' [ 1.5989] '14-May-1999' [ 3.6682] '15-May-1999' [ 5.1284] '16-May-1999' [ 0.4952] '17-May-1999' [ 2.2417] '18-May-1999' [ 0.3579] '19-May-1999' [ 3.6492] '20-May-1999' [ 1.0150] '21-May-1999' [ 1.2445] '22-May-1999' [ 5.5466] '23-May-1999' [ 0.1251] '24-May-1999' [ 1.1195] '25-May-1999' [ 0.3374]...
The new object
srs2 contains all the dates
myfts, but the only data series is
The name of the data series retains its name from the original object,
Note The output from referencing a data series field or indexing a financial time series object is always another financial time series object. The exceptions are referencing the description, frequency indicator, and dates fields, and indexing into the dates field.
the dates and/or the data series values from an object and places
them into a vector or a matrix. The default behavior extracts just
the values into a vector or a matrix. Look at the next example:
srs2_vec = fts2mat(myfts.series2)
srs2_vec = 0.9323 0.5608 1.5989 3.6682 5.1284 0.4952 2.2417 0.3579 3.6492 1.0150 1.2445 5.5466 0.1251 1.1195 0.3374...
If you want to include the dates in the output matrix, provide
a second input argument and set it to
1. This results
in a matrix whose first column is a vector of serial date numbers:
format long g srs2_mtx = fts2mat(myfts.series2, 1)
srs2_mtx = 730251 0.932251754559576 730252 0.560845677519876 730253 1.59888712183914 730254 3.6681500883527 730255 5.12842215360269 730256 0.49519254119977 730257 2.24174134286213 730258 0.357918065917634 730259 3.64915665824198 730260 1.01504236943148 730261 1.24446420606078 730262 5.54661849025711 730263 0.12507959735904 730264 1.11953883096805 730265 0.337398214166607
srs2_mtx contains dates in the first
column and the values of the
series2 data series
in the second. Dates in the first column are in serial date format.
Serial date format is a representation of the date character vector
format (for example, serial date =
1 is equivalent
to 01-Jan-0000). (The serial date vector can include time-of-day information.)
long g display format displays the numbers
without exponentiation. (To revert to the default display format,
format short. (See the
a description of MATLAB display formats.) Remember that both
the vector and the matrix have 101 rows of data as in the original
myfts but are shown truncated here.