CONVERT CHARACTER (SET)

Name:

CONVERT CHARACTER (SET) Type:

Subcommand under SET Purpose:

Specifies how Dataplot will handle character data. Description:

SET CONVERT CHARACTER <ON/CATEGORICAL/IGNORE/ERROR>

These options result in the following actions:

Specifying ERROR continues the current Dataplot action of reporting an error. This is recommended for the case when a file is suppossed to contain only numeric data and the presence of character data is in fact indicative of an error in the data file.
To maintain compatibility with previous versions of Dataplot, this is the default setting.
Specifying IGNORE instructs Dataplot to simply ignore any fields containing character data. No error or warning messages are printed.
Specifying ON instructs Dataplot to read character. The character fields are written to the file "dpzchf.dat" in the current directory.
The first line of this file specifies the number of character fields. Lines 2 thru N+1 (with N denoting the number of character fields) identify the names of the character variables. Each of the remaining lines contain the character fields for one row of character data. Each character variable is written as 24 characters (character fields with more than 24 characters are truncated and those with less than 24 characters are right-padded with spaces) followed by one space.
As with numeric variables, character variable names can be up to eight characters long. Note that Dataplot does not save the character variable names in its internal name table (they are only saved in the "dpchzf.dat" file). Be aware that the "dpchzf.dat" file is overwritten each time a file with character data is encoutered.
This is similar to SET CONVERT CHARACTER ON. However, in addition to creating the character variable, it will create a numeric variable that converts the unique values of the character field to an integer code. Currently, the code values are assigned in the order that the unique values are detected in the file. Up to 1,000 levels are supported (if more than 1,000 levels are required, the remaining levels are all set to "-1").
Note that there will be both a numeric variable and a character variable (in dpzchf.dat) with the same name. The context of how the variable name is used determines whether the numeric or character variable is being referred to (i.e., there are a limited number of commands that specifically refer to the character variables).

There are some restrictions on when Dataplot will try to read character data:

This only applies to the variable read case. That is, READ PARAMETER and READ MATRIX will ignore character fields or treat them as an error.
Dataplot will only try to read character data from a file. When reading from the keyboard (i.e., when READ is specified with no file name), character data will be ignored when a SET CONVERT CHARACTER ON is specified.
This capability is not supported for the SERIAL READ case.
The SET READ FORMAT command does not accept the "A" format specification for reading character fields.

Some of these restrictions may be addressed in subsequent releases of Dataplot.

Syntax:

Examples:

Note:

SET ROW LABEL COLUMN <ival>

where <ival> is an integer value that specifies which column of the data is a row label variable. The values in this column are stored in the internal row label variable. This is demonstrated in the Program 2 example below. Although a row label variable is typically the first column, this is not required.

Note:

If Dataplot encounters one of these characters in a character field, it treats it as the end of the character field (the delimiter will not be part of the string.

If you have character data that will contain one or more of these delimiters, then the character fields need to be enclosed in quotes (either single or double quotes may be used). If the character fields may contain quotes, then use one type (i.e., single or double) as the delimiter and the other type in the character field. At the current time, Dataplot will not accomodate both types of quotes in the character fields.

Note:

The TIC MARK LABEL FORMAT and TIC MARK LABEL CONTENT commands have been updated to use group labels for the tic mark labels.

For details, enter

We anticipate additional use will be made of character data in subsequent versions of Dataplot.

Default:

ERROR (character data will be treated as an error) Synonyms:

None Related Commands:

READ	=	Carries out a column-wise input of data.
CHARACTER CODE	=	Converts character data to a coded numeric variable.
GROUP LABEL	=	Converts character data to a group label variable.
ROWLABEL	=	Define row labels from character data.

Applications:

Input/Output Implementation Date:

Program 1:

 
set convert character on
skip 25
read draft69c.dat rank day month
.
let ig = group label month
x1tic mark label format group label
x1tic mark label content ig
x1tic mark font simplex
x1tic mark angle 45
let xcode = character code month
.
major xtic mark number 12
minor xtic mark number 0
xlimits 1 12
xtic offset 0.5 0.5
.
char box plot
line box plot
fences on
.
box plot y xcode

Program 2:

 
SET CONVERT CHARACTER CATEGORICAL
SET ROW LABEL COLUMN 1
READ TEST_CHAR.DAT IROW Y X1 X2
.
SET WRITE DECIMALS 1
WRITE ROWLABEL Y X1 X2

 
----------------------------------------------------------------------
 ROWLABEL                              Y             X1             X2
----------------------------------------------------------------------
 Row_1                               8.0            1.0            1.0
 Row_2                               2.0            2.0            2.0
 Row_3                               1.0            1.0            3.0
 Row_4                               7.0            2.0            1.0
 Row_5                               3.0            1.0            2.0