DFI.subset | R Documentation |
Function to subset a DFI object efficiently (using binary search) by creating complex filters on indexed columns.
For details about column indexes, refer to DFI
, for information about NA
handling, refer to rowfilters.DFI
.
DFI.subset(DFIobj, filter=NULL, return.indexes=FALSE, sort.indexes=TRUE, colFilter=NULL, drop=NULL)
DFIobj |
a DFI object. |
filter |
a filter object created by functions |
return.indexes |
if TRUE, the row indexes satisfying the filter are returned instead of the DFI subset. |
sort.indexes |
if FALSE the order of the rows or row.index returned will not be necessarily equal to the original order in the DFI object. If TRUE, subsetting will keep the original row/row.indexes order. FALSE usually gives a better performance. |
colFilter |
if |
drop |
if different from |
A subset of the data.frame or matrix wrapped by the DFI object, unless return.indexes==TRUE
in which case an integer vector with the row indexes will be returned.
DFI
,
EQ
,
IN
,
RG
,
NOT
,
AND
,
OR
### create a simple DFIobj DF <- data.frame(Foo=c(3,5,7,1,5,8,7,10), Bar=c("A","B","B","C","B","B","C","A"), Baz=c(TRUE,FALSE), stringsAsFactors=FALSE) DFIobj <- DFI(DF, c("Foo","Bar")) # create a DFI from DF with indexes on "Foo" and "Bar" columns DFI.subset(DFIobj, filter=OR(EQ('Foo',5),EQ('Bar','B')))
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