DataFrameList-class | R Documentation |
Represents a list of DataFrame
objects.
The SplitDataFrameList
class contains the additional restriction
that all the columns be of the same name and type. Internally it is stored
as a list of DataFrame
objects and extends
List
.
In the following code snippets, x
is a DataFrameList
.
dims(x)
:Get the two-column matrix indicating the number of rows and columns over the entire dataset.
dimnames(x)
: Get the list of two CharacterLists,
the first holding the rownames (possibly NULL
) and the second
the column names.
In the following code snippets, x
is a SplitDataFrameList
.
commonColnames(x)
: Get the character vector of
column names present in the individual DataFrames in x
.
commonColnames(x) <- value
: Set the column names of
the DataFrames in x
.
columnMetadata(x)
: Get the DataFrame
of
metadata along the columns, i.e., where each column in x
is
represented by a row in the metadata. The metadata is common
across all elements of x
. Note that
calling mcols(x)
returns the metadata on
the DataFrame
elements of x
.
columnMetadata(x) <- value
: Set the DataFrame
of metadata for the columns.
In the following code snippets, x
is a SplitDataFrameList
. In
general x
follows the conventions of
SimpleList
/CompressedList
with the following addition:
x[i,j,drop]
: If matrix subsetting is used, i
selects
either the list elements or the rows within the list elements as
determined by the [
method for
SimpleList
/CompressedList
, j
selects the columns,
and drop
is used when one column is selected and output can
be coerced into an AtomicList
or IntegerRangesList
subclass.
x[i,j] <- value
: If matrix subsetting is used, i
selects either the list elements or the rows within the list elements
as determined by the [<-
method for
SimpleList
/CompressedList
, j
selects the columns
and value
is the replacement value for the selected region.
DataFrameList(...)
: Concatenates the DataFrame
objects in ...
into a new DataFrameList
.
SplitDataFrameList(..., compress = TRUE, cbindArgs =
FALSE)
: If cbindArgs
is FALSE
, the ...
arguments are coerced to DataFrame
objects and concatenated
to form the result. The arguments must have the same number and
names of columns. If cbindArgs
is TRUE
, the
arguments are combined as columns. The arguments must then be the
same length, with each element of an argument mapping to an
element in the result. If compress = TRUE
, returns a
CompressedSplitDataFrameList
; else returns a
SimpleSplitDataFrameList
.
In the following code snippets, objects in ...
are of class
DataFrameList
.
rbind(...)
: Creates a new DataFrameList
containing
the element-by-element row concatenation of the objects in ...
.
cbind(...)
: Creates a new DataFrameList
containing
the element-by-element column concatenation of the objects in ...
.
transform(`_data`, ...)
: Transforms a
SplitDataFrame
in a manner analogous to the
base transform
, where the columns are List
objects adhering to the structure of _data
.
In the following code snippets, x
is a DataFrameList
.
as(from, "DataFrame")
: Coerces a
SplitDataFrameList
to a DataFrame
, which has a column
for every column in from
, except each column is a
List
with the same structure as from
.
as(from, "SplitDataFrameList")
: By default, simply
calls the SplitDataFrameList
constructor
on from
. If from
is a List
, each element
of from
is passed as an argument
to SplitDataFrameList
, like calling as.list
on a
vector. If from
is a DataFrame
, each row becomes an
element in the list.
stack(x, index.var = "name")
: Unlists x
and
adds a column named index.var
to the result, indicating the
element of x
from which each row was obtained.
as.data.frame(x, row.names = NULL, optional = FALSE,
..., value.name = "value", use.outer.mcols = FALSE,
group_name.as.factor = FALSE)
:Coerces x
to a data.frame
. See as.data.frame on the
List
man page for details (?List
).
Michael Lawrence, with contributions from Aaron Lun
DataFrame
# Making a DataFrameList, which has different columns.
out <- DataFrameList(DataFrame(X=1, Y=2), DataFrame(A=1:2, B=3:4))
out[[1]]
# A more interesting SplitDataFrameList, which is guaranteed
# to have the same columns.
out <- SplitDataFrameList(DataFrame(X=1, Y=2), DataFrame(X=1:2, Y=3:4))
out[[1]]
out[,"X"]
out[,"Y"]
commonColnames(out)
commonColnames(out) <- c("x", "y")
out[[1]]
# We can also create these split objects using various split() functions:
out <- splitAsList(DataFrame(X=runif(100), Y=rpois(100, 5)),
sample(letters, 100, replace=TRUE))
out[['a']]
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