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Dataplot Vol 1 Auxillary Chapter

READ STACKED VARIABLES

Name:
    READ STACKED VARIABLES
Type:
    Input Command
Purpose:
    Reads a list of variables into a single response variable and a corresponding group-id variable.
Description:
    A number of Dataplot commands expect data in the form

      Y X

    where Y is a response variable and X is a group-id variable. For example,

      BOX PLOT Y X
      MEAN PLOT Y X

    However, many data files are in the form where the data for each group is stored as a separate column. The command READ STACKED VARIABLES can be used to read these files into the Y X format needed by many Dataplot commands.

Syntax:
    READ STACKED VARIABLES <file> <y> <groupid> <var-list>
    where <file> is the name of a data file;
                <y> is the response variable where the data will be saved;
                <groupid> is a variable that identifies the group for each row of the response variable;
    and <var-list> is a list of one or more variables to read from the data file.

    The file name is optional. If the file name is omitted, the read will be from the terminal (until an END OF DATA is entered).

    The first variable read will have a group-id value of 1, the second variable read will have a group-id value of 2 and so on.

Examples:
    READ STACKED VARIABLES FILE.DAT Y GROUP X1 X2
    READ STACKED VARIABLES FILE.DAT Y GROUP X1 X2 X3
    READ STACKED VARIABLES FILE.DAT Y GROUP X1 X2 X3 X4
Note:
    This command is similar to the READ MATRIX TO VARIABLES command. The distinction is that the READ MATRIX TO VARIABLES returns both a row-id and a column-id variable. The READ STACKED VARIABLES just returns a group-id variable (i.e., a column-id).

    The STACK command is also similar. However, it works on variables that have already been read into Dataplot.

Note:
    By default, DATAPLOT does free format reads. However, it has the capability for supporting FORTRAN style formats. Formatted reads can be about 10 times faster on many systems. This can be helpful for large data files. Enter HELP READ FORMAT for more details.
Note:
    Blank lines in data files are ignored.
Note:
    DATAPLOT supports the ability to embed comment lines within the data file. Enter HELP COMMENT CHECK for details.
Note:
    In order to determine whether the first argument is a file name or a variable name, it looks for a period in the name. If it finds one, it assumes a file name. If it does not, it assumes a variable name. If your file name does not contain a period, attach a trailing period (no spaces) to the file name on the READ STACKED VARIABLES command.
Note:
    DATAPLOT has no restrictions on the file name other than it be a valid file name on the local operating system and that it contain a period "." in the file name itself or as a trailing character. DATAPLOT strips off trailing periods on those systems where it is appropriate to do so. On systems where trailing periods can be a valid file name (e.g., Unix), DATAPLOT tries to open the file with the trailing period. If this fails, it then tries to open the file with the trailing period stripped off.

    Some users prefer to give all data files a ".DAT" or ".dat" extension. Although this is a useful method for keeping track of data files, it is strictly a user convention and is not enforced by DATAPLOT in any way.

Note:
    File names are case sensitive on Unix file systems. For Unix, DATAPLOT attempts to open the file as given. If this fails, it attempts to open the file as all upper case characters. If this fails, it attempts to open the file as all lower case characters. All other currently supported systems are not case sensitive regarding file names.

    As a further caution for Unix hosts, certain expansion characters (specifically ~ to refer to your home directory) are interpreted by the shell and are not recognized by the Fortran compiler. These expansion characters are interpreted as literal characters and do not yield the intended file name.

Default:
    None
Synonyms:
    None
Related Commands: Applications:
    Data Input
Implementation Date:
    2008/3
Program:
     
    SKIP 25
    READ STACKED VARIABLES MONTGOME.DAT  Y GROUP X1 X2 X3
    .
    TITLE Mean Plot
    TITLE OFFSET 2
    TITLE CASE ASIS
    XLIMITS 1 3
    TIC OFFSET UNITS DATA
    XTIC OFFSET 0.5  0.5
    MAJOR XTIC MARK NUMBER 3
    MINOR XTIC MARK NUMBER 0
    XTIC MARK LABEL FORMAT ALPHA
    XTIC MARK LABEL CONTENT Large Medium Small
    TIC MARK LABEL CASE ASIS
    Y1LABEL Mean Percentage
    X1LABEL Group
    LABEL CASE ASIS
    CHARACTER X BLANK
    LINE BLANK SOLID
    .
    MEAN PLOT Y GROUP
        
    plot generated by sample program

Date created: 1/6/2009
Last updated: 1/6/2009
Please email comments on this WWW page to alan.heckert@nist.gov.