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	Introduction to SPSS: Part II
	Research Computing Support Group res-consult@virginia.edu © 1996,1997,1998, 1999 by the Rector and Visitors of the University of Virginia

1. Reading Other Types Of Data
   1. Reading In A Microsoft Excel File
   2. Reading In A Tab-Delimited Data File
2. Moving Between SPSS on Different Platforms
   1. Unix
   2. Macintosh
3. Basics of using Syntax
   1. Opening a New SPSS Syntax Editor Window
   2. Creating SPSS Syntax
   3. Running Command Syntax
4. Examples of Basic Syntax Commands
   1. Open an Existing SPSS Data File
   2. Data File Documentation
      1. Comments
      2. File Label
      3. Document
5. Editing User Preferences
6. Getting Help

1. Reading Other Types Of Data

The following are some types of formats which can be read into SPSS or into which you can save your SPSS data file:

• SPSS (*.sav). SPSS format. Data files saved in SPSS format cannot be read by versions of the software prior to version 7.5.
• SPSS 7.0 (*.sav). SPSS 7.0 for Windows format. Data files saved in SPSS 7.0 format can be read by SPSS 7.0 and earlier version of SPSS for Windows--but do not include defined multiple response sets or Data Entry for Windows information.
• SPSS/PC+ (*.sys). SPSS/PC+ format. If the data file contains more than 500 variables, only the first 500 will be saved. For variables with more than one defined user-missing value, additional user-missing values will be recoded into the first defined user-missing value.
• SPSS portable (*.por). SPSS portable format that can be read by versions of SPSS on other operating systems (for example, Macintosh or UNIX).
• SAS data sets (*.sas7bdat, *.saspor) SAS data sets, version 6 and 8, as well as SAS Transport (portable) file formats can be read into SPSS
• Tab-delimited (*.dat). ASCII text files with values separated by tabs.
• Fixed ASCII (*.dat). ASCII text file in fixed format, using the default write formats for all variables. There are no tabs or spaces between variable fields.
• Excel (*.xls). Microsoft Excel spreadsheet. The maximum number of variables is 256.

1.1 Reading In A Microsoft Excel File

As with the tab-delimited data, reading in an Excel file is straightforward.

Once the Excel file is in this format, you can read it into SPSS by simply going to File: Open, select Excel from under the option box "Files of Type," and locate the file.

Once you have located the file, if it's a newer Excel file, (Office 98 or later) you are opening, SPSS will display the following dialog box:

This box is asking whether the Excel file has variable names that appear in the first row of the data set. If you do have such variable names, check this box as above. Doing so, makes SPSS assign names to each of the new variables. You can also select which worksheet to read in if there are multiple worksheets in the file.

1.2 Reading In A Tab-Delimited Data File

To read in plain ASCII text data that is delimited by tabs (a common raw data format), you simply need to go to File: Open, select Tab-Delimited from under the option box "Files of Type," and locate the file.

The text import wizard will open to walk you through the import of your text file. You will need to select the delimiter, formats for your variables, whether you have variable names in the first row of the data set, etc.

2. Moving Between SPSS on Different Platforms

2.1 Unix

Moving SPSS files between Unix and Windows involves no translation or conversion. SPSS data files (*.sav) or syntax files (*.sps) can be sent or retrieved from your Unix account using a transfer utility such as FTP or the new Home Directory service at UVa. It is important to remember, however, that data files are binary files (and thus must be transferred in BINARY mode) and syntax files are text files (and thus must be transferred in ASCII mode).

Output files created in newer versions of SPSS for Windows (*.spo) cannot be opened in SPSS for Unix. If you want to open in SPSS for Unix your output generated in SPSS for Windows, you must first save the Windows output as a text file.

Moving Files between Windows and Unix:

• Data files (*.sav): no conversion (transfer in binary mode)
• Syntax files (*.sps): no conversion (transfer in ASCII mode)
• Output files: SPSS for Unix output files (*.lst) can be read by SPSS 10 for Windows but they will be opened as a syntax window. SPSS for Unix cannot read SPSS for Windows output files (*.spo) unless they have been saved as text files.

Running SPSS for Unix in Batch Mode: At the Unix command prompt, type:

spss -m < example1.sps > example1.lis

where "<" is the Unix re-direction symbol for input, and ">" is the symbol for output
and "example1.sps" is your file of SPSS commands (syntax) and "example1.lis" will be where SPSS puts the results of your commands after it runs them.

Running SPSS for Unix in X-Windows Mode: If running Exceed and logged onto a Unix serveron which SPSS is available, then at the Unix command prompt, type:

spss

Moving SPSS files between Macintosh and Windows involves a bit more work than between Unix and Windows. SPSS for Mac data files (*.sav) cannot be read by SPSS for Windows (or vice versa). Instead, you must first save the data file as an SPSS portable file (*.por) which can be read by any SPSS system (Unix, Windows, Macintosh). Portable files are ASCII files and thus should be transferred in ASCII mode if using a transfer utility (e.g. FTP).

SPSS syntax files (*.sps) are fully portable between SPSS for Windows and Mac. If transferred, they should be transferred in ASCII mode.

Output files can be transferred without conversion between SPSS for Mac and versions of SPSS for Windows prior to 7.5.x. In versions of SPSS for Windows 7.5.x and later, the output files (*.spo) cannot be transferred to SPSS for Mac without first saving the output file as a text file (*.txt). Output files from SPSS for Mac can be opened in newer versions of SPSS for Windows, but they will be opened in a syntax window.

Moving Files between Windows and Macintosh:

• Data files (*.sav): must be converted to SPSS portable files (.por) (transfer in ASCII mode)
• Syntax files (*.sps): no conversion (transfer in ASCII mode)
• Output files: SPSS for Macintosh output files (*.lst) can be read by SPSS 8.0 for Windows but they will be opened as a syntax window. SPSS for Macintosh cannot read SPSS for Windows output files (*.spo) unless they have been saved as text files.

In order to begin issuing SPSS syntax commands, you must have a Syntax Editor window open. If you do not currently have a Syntax window open, then do the following: Under File, select New, and then Syntax.

The Syntax Editor window looks like this:

Most commands are accessible from the menus and dialog boxes. However, some commands and options are available only by using the command language. The command language also allows you to save your jobs in a syntax file so that you can repeat your analysis at a later date.

Keep in mind the following simple rules when editing and writing command syntax:

• Each command must begin on a new line and end with a period (.).
• Most subcommands are separated by slashes (/). The slash before the first subcommand on a command is usually optional.
• Variable names must be spelled out fully.
• Text included within apostrophes or quotation marks must be contained on a single line.
• Each line of command syntax cannot exceed 80 characters.
• A period (.) must be used to indicate decimals, regardless of your Windows regional settings.
• Variable names ending in a period can cause errors in commands created by the dialog boxes. You cannot create such variable names in the dialog boxes, and you should generally avoid them.

FREQUENCIES
VARIABLES=JOBCAT GENDER
/PERCENTILES=25 50 75
/BARCHART.

and

freq var=jobcat gender /percent=25 50 75 /bar.

are both acceptable alternatives that generate the same results.

While it is possible to open a syntax window and type in commands, you can also let SPSS help you build your syntax file using one of the following methods:

1. Pasting command syntax from dialog boxes. The easiest way to build a command syntax file is to make selections in dialog boxes and select Paste instead of Ok. This puts the syntax for the selections into the designated syntax window. By pasting the syntax at each step of a lengthy analysis, you can build a job file allowing you to repeat the analysis at a later date. In the syntax window, you can run the pasted syntax, edit it, and save it in a syntax file.

2. Copying syntax from the output log. You can build a syntax file by copying command syntax from the log that appears in the Viewer. To use this method, you must select Display commands in the log in the Draft Viewer dialog box before running the analysis. Each command will then appear in the Output Viewer along with the output from the analysis.

If you want to copy the syntax that appears in the output Viewer, double-click on the log window that contains the syntax that you want to copy, highlight the syntax, select Edit:Copy, switch to the Syntax Editor, and select Edit:Paste.

3. Copying syntax from the journal file. By default, all commands executed during a session are recorded in a journal file named SPSS.JNL (set with Options on the Edit menu using General tab). You can edit the journal file and save it as a syntax file that you can use to repeat a previously run analysis. The journal file is a text file that can be edited like any other text file. Because error messages and warnings are also recorded in the journal file along with command syntax, you must edit out any error and warning messages that appear before saving the syntax file. Save the edited journal file with a different filename. Because the journal file is automatically appended or overwritten for each session, attempting to use the same filename for a syntax file and the journal file may yield unexpected results.

If you have more than one open Syntax Editor window, command syntax is pasted into the designated Syntax Editor window. If you have more than one open Viewer window, output is routed to the designated Viewer window. The designated windows are indicated by a red exclamation point (!) in the status bar. You can change the designated windows at any time. One use of this feature is to have more than one OUTPUT window open and be able to save some procedures to one automatically, then switch the designated window to the other OUTPUT file and run additional procedures that save into that one.

The designated window should not be confused with the active window, which is the currently selected window. If you have overlapping windows, the active window appears in the foreground. If you open a new Syntax Editor or Viewer window, that window automatically becomes the active window and the designated window.

3.3 Running Command Syntax

Once you've created commands in the syntax window, you must submit them to be processed by SPSS. To submit commands, follow these steps:

1. Highlight the commands you want to run in the syntax window.
2. Submit the commands in one of the following ways:
   1. Click the Run button (the right-pointing triangle) on the syntax window toolbar. The Run button on the Syntax Editor toolbar runs the selected commands or the command where the cursor is located if there is no selection; or
   2. Select one of the choices from the Run menu located on the menu bar:
      1. All. Runs all commands in the syntax window.
      2. Selection. Runs the currently selected commands. This includes any commands partially highlighted.
      3. Current. Runs the command where the cursor is currently located.
      4. To End. Runs all commands from the current cursor location to the end of the command syntax file.

COMPUTE bad=1 .
EXECUTE.

To open an SPSS data file, use the following syntax:

GET FILE = 'G:\apps\win32\spss8\examples\bank.sav' .

Submit this command to SPSS and the requested file should appear in the Data Editor.

4.2 Data File Documentation

It's best to leave a trail of comments and information behind you as you plunge through the data. Using variable labels and value labels, comments, file labels, and document commands all make the data analysis process that much smoother and easier to re-create or explain to someone else should the need arise.

4.2.1 Comments

Comments can be put anywhere in an SPSS file. They are highly recommended as a way to annotate your command program and output listing for future reference. You can indicate a comment in two ways:

1. By starting the line with an asterisk.
2. By starting the line with the command COMMENT.

*/This is a comment */
GET FILE = 'G:\apps\win32\spss8\examples\bank.sav' .

or

COMMENT This is a comment
which continues on the second line
GET FILE = 'G:\apps\win32\spss8\examples\bank.sav' .

The File Label provides a descriptive label for the data file. The File Label is printed on the first line of each page of output displayed by the program. The label can be up to 60 characters long. For example:

FILE LABEL 'bank data for discrimination lawsuit' .

4.2.3 Document

The DOCUMENT command saves a block of text of any length in an SPSS-format data file. The basic command is DOCUMENT followed by any length of text. The text can be entered on as many lines as needed. Blank lines can be used to separate paragraphs. A period at the end of a line terminates the command, so you should not place a period at the end of any line but the last. For example,

 

DOCUMENT

This file contains employee personnel information from bank personnel records. It should be treated as confidential .

5. Editing User Preferences

SPSS allows you to customize many aspects of the program to suit your preferences.  By selecting Options under the Edit menu, you can change such features as how your variables are displayed in output, the format of charts, where page breaks occur in your output, as well as the font used -- to name just a few.

  Some changes from the default that we recommend and that are used in all of the ITC Public Computing facilities and classrooms are:

• General Tab: Check the YES button on the "Open Syntax Window at Startup".
  You may also want to change the "Variable Lists" choices. If I know the data well, I prefer SPSS shows me variable names and does it in File order. However if I'm unfamiliar with the data, it's helpful to have it use the variable labels and present the list of them in alphabetic order. This affects how the variables are displayed in any of the menu windows where you choose variables.
  * Notice that SPSS records all of your mouse clicks into a journal file, the "Session Journal" section shows you the name of the file into which SPSS writes what you do as well as provides you with an opportunity to append to it from session to session or overwrite it. We recommend you append to it. You will have to periodically delete it as it will grow very large (> 10MB) if you use SPSS often.
  
• View Tab: Check the YES button on the "Display Commands in Log". When you're learning SPSS or trying to debug a problem it's helpful to have SPSS echo your commands (from your menu choices) into the OUTPUT window so you can see what you asked and what SPSS did all in one place. If you're preparing for a presentation or paper, you may want to turn this back off, so your OUTPUT window has only your results in it. Notice on this tab, you can also choose what additional notes and messages SPSS puts in your OUTPUT.

Below is a brief explanation of some of the features on each of the Tabs in the dialogue box:

• General: How the journal files is maintained, how variables are displayed in lists, which windows are opened upon start-up, etc.
• Viewer Options: Controls how output is displayed including page size, alignment, and titles created by the TTLE and SUBTITLE commands.
• Draft Viewer: Controls which items are displayed when you run procedures, page breaks, and settings for pivot tables.
• Output Label: Controls the display of variable and value information in the output outline and pivot table, including the ability to display labels.
• Chart: Controls the height and width of charts, types of fill patterns used, and grid lines.
• Data Options: Control transformation and merge options for data, as well as display information for variables created using Recode and Compute.
• Interactive: Controls aspects of interactive charting.
• Pivot Tables: Controls display of tables in output outline.
• Currency: Controls how currency is displayed and allows the creation of custom formats.
• Script: Allows you to create a script, which is a collection of subroutines associated with procedures, which can be run automatically to create certain types of output objects.

Statistical Consulting hours: For the hours when a statistical computing consultant is available, please contact the Research Computing Support Center by telephoning 243-8800 or e-mailing res-consult@virginia.edu

Helpful Web Pages:

• SPSS Help by ITC
• Research Computing Support

Research Computing Support Homepage