Help System (web edition)

SELECT=<Boolean expression> 
selects observations satisfying the alternative conditions given by
<Boolean expression>=A+B+C+...   (read A or B or C or ...)
where each of the conditions A,B,C,... (say A) is written as
A=A1*A2*A3*...  (read A1 and A2 and A3 and ...) .
Each condition A1,A2,A3,... must be given as a specification of the
form
     A1=<variable>,<lower_limit>,<upper_limit>   (as in IND)
or
     A1=<string_variable>:<case1>,<case2>,...    (as in CASES)
Any words can be used in place of A1,A2,A3,...,B1,B2,B3,...

Please note that SELECT will be considered only after the observation
has passed potential IND and CASES conditions.
                                           (Example on the next page)

Example:
IND=Income,18000,40000 CASES=Service:5,6,7,8,9
SELECT=North*Over10000+South*Over20000
North=Province:OUL,LAP South=Province:UUS,KYM,TUR
Over10000=Popul,10000,500000  Over20000=Popul,20000,500000

selects cases where
18000<=Income<=40000  and  Service=5,6,7,8 or 9
and
    either  Province is OUL or LAP         and  Popul>=10000
    or      Province is UUS or KYM or TUR  and  Popul>=20000
                                    (New form of SELECT on next page!)


The SELECT specification can also be written with negations
(a `!' in front of a Boolean expression)
and with parentheses.
Example:
   SELECT=(A+B)*(C+!D)   equals to SELECT=A*C+A*!D+B*C+B*!D
where A,B,C,D must be given as elementary conditions of IND or CASES type.
For example, A=Quality:1,3,7 B=Length,12,20 .

In complicated expressions, space is saved by using short names for
elementary conditions since Survo transforms expressions first to the
original form without parentheses.

  S = More information on selection of observations