We're talking about "true" and "false" here and how to combine them. For example, if you're looking at census data and you want to find women over 60 who are either married or divorced, then this expression will filter out all the other people in the census file:
The comparison operators =, <, and > can be found on the formula editor's keypad. You can also find ≤
, ≥
, ≠
by holding down Ctrl (Win) Option (Mac).
· Express the not
of an expression (the negative of an expression) by positioning the cursor in front of the expression and clicking the not key on the formula editor keypad.
· You can use and
and or
to string logical expressions together.
· When in doubt about which expressions are evaluated first, use parentheses to force the evaluation order you want.
· "True" and "false" are allowed values for attributes, so you can write a formula for an attribute that returns a Boolean value.
From the keyboard:
· For and
, make sure the preceding expression has parentheses around it and type the word and
.
· For and
, type &
. This has the same effect as the keypad button.
· For or
, make sure the preceding expression has parentheses around it and type the word or
.
· For or
, type Ctrl+Shift+O (Win) Option+Shift+O (Mac) (that's the letter "O" as in "Oscar").
· For not
, type ~. (~ is the tilde key, usually in the upper left of your keyboard.)
Key Curriculum Press/Key College Publishing www.keypress.com/fathom |