SPSS® 12.0 Command Syntax Reference

256 COMPUTE
• The last two examples above illustrate the use of parentheses to control the order of
execution. For a case with value 2 for X and Y, TEST equals 0.5, since 2 divided by 2 (X/Y)
is 1, the square root of 1 is 1, truncating 1 returns 1, and 1 times 0.5 is 0.5. However,
PARENS equals 0 for the same case, since SQRT(X/Y) is 1, 1 times 0.5 is 0.5, and
truncating 0.5 returns 0.
Statistical Functions
COMPUTE NEWSAL = SUM(SALARY,RAISE).
COMPUTE MINVAL = MIN(V1,V2,V3,V4).
COMPUTE MEANVAL = MEAN(V1,V2,V3,V4).
COMPUTE NEWMEAN = MEAN.3(V1,V2,V3,V4).
• NEWSAL is the sum of SALARY plus RAISE.
• MINVAL is the minimum of the values for V1 to V4.
• MEANVAL is the mean of the values for V1 to V4. Since the mean can be computed for one,
two, three, or four values, MEANVAL is assigned a valid value as long as any one of the
four variables has a valid value for that case.
• In the last example above, the .3 suffix specifies the minimum number of valid arguments
required. NEWMEAN is the mean of variables V1 to V4 only if at least three of these
variables have valid values. Otherwise, NEWMEAN is system-missing for that case.
Missing-Value Functions
MISSING VALUE V1 V2 V3 (0).
COMPUTE ALLVALID=V1 + V2 + V3.
COMPUTE UM=VALUE(V1) + VALUE(V2) + VALUE(V3).
COMPUTE SM=SYSMIS(V1) + SYSMIS(V2) + SYSMIS(V3).
COMPUTE M=MISSING(V1) + MISSING(V2) + MISSING(V3).
• The MISSING VALUE command declares value 0 as missing for V1, V2, and V3.
• ALLVALID is the sum of three variables only for cases with valid values for all three
variables. ALLVALID is assigned the system-missing value for a case if any variable in the
assignment expression has a system- or user-missing value.
• The VALUE function overrides user-missing value status. Thus, UM is the sum of V1, V2,
and V3 for each case, including cases with value 0 (the user-missing value) for any of the
three variables. Cases with the system-missing value for V1, V2, and V3 are system-missing.
• The SYSMIS function on the third COMPUTE returns the value 1 if the variable is systemmissing.
Thus, SM ranges from 0 to 3 for each case, depending on whether variables V1,
V2, and V3 are system-missing for that case.
• The MISSING function on the fourth COMPUTE returns the value 1 if the variable named is
system- or user-missing. Thus, M ranges from 0 to 3 for each case, depending on whether
variables V1, V2, and V3 are user- or system-missing for that case.