Subset Dialog Function

DESCRIPTION:

The function called by the Subset dialog. This function is used to create a subset of a data.frame based on a specified subset expression. This subset may be indicated by either returning the data.frame supplemented with a logical column indicating group membership, or by returning a data.frame which is a subset of the original data.frame.

USAGE:

menuSubset(data, subset.expression, subset.columns, result.type="Data Set",  
     subset.col.name="subset", save.name=NA, show.p=.Options$show.data.in.view, 
     keep.na.rows=F) 

REQUIRED ARGUMENTS:

data
Data.frame from which to create the subset.
subset.expression
List such that unlist of the evaluated expression contains row names, row numbers, or a logical vector indicating which rows to include in the subset. This is specified as a list so that users may specify "1, 2, 3" or "Mileage > mean(Mileage)" in the Subset dialog and obtain the specified rows or the result of evaluating the conditional expression.

OPTIONAL ARGUMENTS:

subset.columns
Vector or list of column names or numbers specifying which columns to include in the subset data frame. If missing, all columns are included.
result.type
Character string "Data Set" or "Add Column". If "Data Set", the result will be a data.frame which contains a subset of the rows in data. If "Add Column", the result will be a data.frame with all of the rows of data and a new logical column indicating whether each row is in the specified subset.
subset.col.name
Character string giving name for new subset indicator column if result.type is "Add Column".
save.name
character string giving name under which to save result. If this is specified the result will be assigned to the working database under the given name, and will also be returned invisibly.
show.p
logical flag: if TRUE, save.name is specified, and the Windows S-PLUS GUI is active, the result will be displayed in a Data Window.
keep.na.rows
logical flag: if TRUE the rows for which the condition is NA will be retained in the subset. By default rows for which the condition is NA are excluded from the subset.

VALUE:

Data.frame as described above under result.type.

EXAMPLES:

menuSubset(fuel.frame,list(1,2,3)) 
menuSubset(fuel.frame,list(Mileage>mean(Mileage)))