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1.2. Objects

All information in EViews is stored in objects. Each object consists of a collection of information related to a particular area of analysis. For example, a series object is a collection of information related to a set of observations on a particular variable. An equation object is a collection of information related to the relationship between a collection of variables. Together with the data information, EViews also associates procedures which can be used to process the data. For example, an equation object contains all of the information relevant to an estimated relationship, you can examine results, perform hypothesis and specification tests, or generate forecasts at any time. Managing your work is simplified since only a single object is used to work with an entire collection of data and results.

Each object contains various types of information. For example, series, matrix, vector, and scalar objects contain numeric data while equations and systems contain complete information about the specification of the equation or system, the estimation results. Graphs and tables contain numeric, text, and formatting information. Since objects contain various kinds of data, you will work with different objects in different ways.

EViews provides you with different tools for each object. These tools are views and procedures which often display tables or graphs in the object's window. Using procedures you can create new objects. For example, equation objects contain procedures for generating new series containing the residuals, fitted values, or forecasts from the estimated equation. You select procedures from the Proc menu and views from the View on the object's toolbar or from the EViews main menu.

There are a number of different types of objects, each of which serves a unique function. Most objects are represented by a unique icon which is displayed in the workfile window. The basic object icons are:

Figure 1.2: Object Icons

Object Icons

In order to create an object, create or loaded a workfile first and then select Object/New Object from the main menu. You will see the New Object dialog box where you can click on the type of object you want to create. For some object types, a second dialog box will open prompting you to describe your object in more detail. For example, if you select Equation, you will see a dialog box prompting you for additional information.

Once you have selected your object, you can open it by double clicking anywhere in the highlighted area. If you double click on a single selected object, you will open an object window. If you select multiple graphs or series and double click, a pop-up menu appears, giving you the option of creating and opening new objects (group, equation, VAR, graph) or displaying each of the selected objects in its own window. Note that if you select multiple graphs and double click or select View/Open as One Window, all of the graphs will be merged into a single graph and displayed in a single window. Other multiple item selections are not valid, and will either issue an error or will simply not respond when you double click. When you open an object, EViews will display the view that was displayed the last time the object was opened (if an object has never been opened, EViews will use a default view). The exception to this general rule is for those views that require significant computational time. In this latter case, the current view will revert to the default.

An alternative method of selecting and opening objects is to "show" the item. Click on the Show button on the toolbar, or select Quick/Show from the menu and type in the object name or names. Showing an object works exactly as if you first selected the object or objects, and then opened your selection.

Object windows are the windows that are displayed when you open an object or object container. An object's window will contain either a view of the object, or the results of an object procedure. One of the more important features of EViews is that you can display object windows for a number of items at the same time.

Let us look again at a typical object window:

Figure 1.3: Object Window in EViews

Object Window in EViews

Here, we see the series window for RETURNS. At the top of the window there is a toolbar containing a number of buttons that provide easy access to frequently used menu items. These toolbars will vary across objects. There are several buttons that are found on all object toolbars:

• View button lets you change the view that is displayed in the object window. The available choices will differ, depending upon the object type.

• Proc button provides access to a menu of procedures that are available for the object.

• Object button lets you manage your objects. You can store the object on disk, name, delete, copy, or print the object.

• Print button lets you print the current view of the object (the window contents).

• Name button allows you to name or rename the object.

• Freeze button creates a new object graph, table, or text object out of the current view.

There are two distinct methods of duplicating the information in an object: copying and freezing. If you select Object/Copy from the menu, EViews will create a new untitled object containing an exact copy of the original object. By exact copy, we mean that the new object duplicates all the features of the original (except for the name). It contains all of the views and procedures of the original object and can be used in future analyses just like the original object. You may also copy an object from the workfile window. Simply highlight the object and click on Object/Copy Selected or right mouse click and select Object/Copy, then specify the destination name for the object.

The second method of copying information from an object is to freeze a view of the object. If you click Object/Freeze Output or press the Freeze button on the object's toolbar, a table or graph object is created that duplicates the current view of the original object. Freezing the view makes a copy of the view and turns it into an independent object that will remain even if you delete the original object. A frozen view shows a snapshot of the object at the moment you pushed the button. The primary feature of freezing an object is that the tables and graphs created by freezing may be edited for presentations or reports. Frozen views do not change when the workfile sample or data change.

To delete an object or objects from your workfile, select the object or objects in the workfile directory and click Delete or Object/Delete Selected on the workfile toolbar.

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