RoughSets (version 1.0-0)

SF.read.DecisionTable: The importing function

Description

It is a additional function used to import dataset from files and then construct them into the standard decision table.

Usage

SF.read.DecisionTable(filename, decision.attr = NULL,
    indx.nominal = NULL, ...)

Arguments

filename

a file name that contains objects/data.

decision.attr

a index position of decision attribute. When we ignore this parameter, the function will treat the data as an information system or newdata/testing data. In other words, we must define the index of decision attribute if we have the decision attr

indx.nominal

a indexes of nominal values. It is used to define specific indexes as nominal attributes.

...

other parameters which are involved in read.table function. See read.table.

Value

• A "DecisionTable" class which is the standard decision table. See SF.asDecisionTable.

Details

It is used to read a dataset from files with the following format: ".csv", ".txt", ".dat", and ".xls", into decision table format. The data should be in table format containing rows and columns without header, where every row represents every object/instance while columns represent attributes of the objects.

The output of this function is a decision table which fulfills a standard format of RoughSets package (See SF.asDecisionTable). In order to construct the decision table, especially in determining description of attributes, this function uses simple heuristic techniques as follows:

• string values: they will be recognized as nominal/symbolic values.
• integer values: they will be recognized as continuous/real values.
• decimal/real values: they will be recognized as continuous/real values.
• indx.nominal: the attributes that are set in this parameter will be assigned as nominal values.

Examples

#############################################################
## Example 1: dataset saved in a file
#############################################################
## Let us assume we have the following data which has been already saved to the file "tes.dat"
data <- data.frame(c(0.12, 0.23, 0.24), c(1,3,2), c(10, 12, 18), c("a", "a", "b"), c(1, 1, 2))
write.table(data, file = "tes.dat", row.names = FALSE, col.names = FALSE,
                    fileEncoding ="")

## Then we would generate decision table from tes.dat file.
## in this case, we want to define that second and third attributes are nominal and continuous,
## respectively.
decision.table <- SF.read.DecisionTable(filename = "tes.dat", decision.attr = 4,
                  indx.nominal = 2, sep= " ", col.names = c("v1", "v2", "v3", "v4", "o1"))