SPSS Portable Files
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SPSS Portable files (previously called Export files) were designed to transfer SPSS data sets between different kinds of computers.  You can use them to move your data to and from mainframe SPSS-X and SPSS for the PC.


Standard extension:  por


Reading and Writing SPSS Portable Files

Long variable names, used in Version 12 and above, are now supported.


Long strings, used in Version 13, are read and written.


Reading SPSS Portable Files

Mainframe Portable files should be transferred to your PC using an error-correcting communications protocol.  It is quite difficult to check these files visually for errors and certain errors may fatally affect the ability of Stat/Transfer to interpret the file.


Writing SPSS Portable Files

When Stat/Transfer writes Portable files, it does so with up to ten base-thirty digits of precision.


Missing Data

SPSS allows for three numeric missing values.  By default, on input these are recognized by Stat/Transfer.  The default behavior can be changed with the User Missing Values selection of the Options dialog box.


By default (when the option Map to extended (a-z) missing is left unchecked), all user missing values that are selected according the options Use All/Use First/Use none will go to a single missing value which will then be converted to the "system" missing value in the target package ('.' in SAS or Stata, for example).


If the option Map to extended (a-z) missing is checked, user missing values will be mapped, if possible, to extended missing values in formats that support them (SAS, ACSII, or Stata).


If possible, the first letter of the value label will be used as the missing value. For instance, if the value '0' is a user missing value and is labeled as "inapplicable", it will be mapped to '.i'.  This mapping will only occur for missing values that are computed with an equal operator.


If there is no label, or if the missing letter has already been used, the missing value will be mapped sequentially to '.a' - '.c'.


On output to SPSS, missing values are set to the SPSS system missing value.


Output Variable Types

The output variable type that results from each target variable type is given in the following table:



Target Type

Output Type


byte

int

long

float

double

Number


string

String


date

Date


time

date/time

Character (written using ASCII format options currently in effect)