User guide

Using Excel with Datastream Advance for Office
Page 24 of 38
4 USING EXPRESSIONS
THE EXPRESSION PICKER
You use the Expression Picker to select expressions. Click the Expression Picker button, to display the
Expression Picker dialog.
The Expression Picker dialog
Show:
Use the Show: drop down box to display: all, local, or global expressions.
Search
Type either the first few letters of the title, or expression in the Find: field.
New Expression
Click the New Expression button to display the Expression Builder, which you use to create new expressions.
Edit
Click the Edit button to edit an expression you have created in the Expression Builder. You cannot edit a
Datastream global expression, but you can use it as a starting point for making a new local expression.
Refresh
Click the Refresh button to up-date the list of expressions held on Datastream.
The Grid Last Downloaded: date and time tells you when the list was last downloaded.
A list of all the expressions available is displayed in the Expression Picker dialog. Each time you create a new
expression this list is automatically updated. When new Datastream global expressions are created, you need to
download them from Datastream using the Refresh facility.
USING THE EXPRESSION BUILDER
You can create and edit your own expressions using Datastream‟s Expression Builder, where you can select the
individual components that make up your expressions.
The Expression Builder dialog
The left window is the work area where you build your expression. Each element of the expression, for
example, a series, is shown as an individual line, which you can edit. Each line element is described in the
adjacent window.
Use the buttons on the toolbar, left of the work area, to enter the individual elements (e.g. series, datatypes,
numbers) that make up your expression.
The work area cursor draws a rectangular box around line elements that are logically grouped. For
example, inserting the function LAG# into the expression also inserts a symbolic series X and a time
period. If you delete LAG#, you will also delete the series and time period that belong to it.
As you build up an expression (max. 78 characters), the expression formula is displayed in the Expression
field for checking.
Expert users can type their expressions in the Expression field - pressing ENTER then expands the
expression into the work area, which can then be edited.
The description you type in the Expression Title field (max. 30 characters) will be saved along with the
expression details and displayed in the Expression Picker for identification.