Chapter 5: Getting Started with ADePT
Variable Expressions The following operators can be used in expressions: Operator
Description
+ abs = ^
– sign == pow
round min ceiling
truncate max floor
*
sqrt
/
basic mathematical operators equality check operators exponent (e.g., x^2 is x squared), power (e.g., pow(4,2) is 42 = 16), and square root shortening operators range operators
Variable expressions can include constants, and strings can be used for variables that are of type string. Expression examples are as follows: Expression x=1 x=y+z x=y=1 x = 23 if z == . x = Log(y) if z = 1 s = “test”
Description sets all variable x observations to 1 sets variable x observations to y observation plus z observation sets variable x observations to 1 (true) if y is 1; otherwise, sets variable x observations to 0 (false) sets variable x observations to 23 if z is missing ( . ); otherwise, sets to. sets variable x observations to log of y observations if z is 1; otherwise, sets to. sets all variable x observations to the string “test”
Note: The periods ( . ) in the table above represent system-missing values. This symbol is defined in SPSS® and is used to indicate missing data in datasets.
Another example: To simulate the impact on poverty of a 10 percent increase in incomes of households with more than 4 members, replace the existing income variable using this expression: income = income*1.1 if hhsize > 4. Deleting Variables You can remove variables from the working copy of a dataset that ADePT uses for its calculations. This operation does not change the original dataset. Native variables, as well as generated and replaced variables, can be deleted. 1. In the dataset Variables tab, right-click in the row containing the variable you want to delete, then click Drop Variable [variable name] in the pop-up menu. 2. In the Confirmation dialog, click the Yes button.
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