DataFrame-utils {S4Vectors} | R Documentation |
Common operations on DataFrame objects
Description
Common operations on DataFrame objects.
Splitting
In the code snippet below, x
is a DataFrame object.
split(x, f, drop = FALSE)
:-
Splits
x
into a SplitDataFrameList object, according tof
, dropping elements corresponding to unrepresented levels ifdrop
isTRUE
.
Looping
In the code snippet below, x
is a DataFrame object.
by(data, INDICES, FUN, ..., simplify = TRUE)
:-
Apply
FUN
to each group ofdata
, a DataFrame, formed by the factor (or list of factors)INDICES
. Exactly the same contract asas.data.frame
.
Subsetting based on NA content
In the code snippets below, x
is a DataFrame object.
na.omit(object)
:-
Returns a subset with incomplete cases removed.
na.exclude(object)
:-
Returns a subset with incomplete cases removed (but to be included with NAs in statistical results).
is.na(x)
:-
Returns a logical matrix indicating which cells are missing.
complete.cases(x)
:-
Returns a logical vector identifying which cases have no missing values.
Transforming
In the code snippet below, x
is a DataFrame object.
transform(`_data`, ...)
:adds or replaces columns based on expressions in
...
. Seetransform
.
Statistical modeling with DataFrame
A number of wrappers are implemented for performing statistical procedures, such as model fitting, with DataFrame objects.
Tabulation
xtabs(formula = ~., data, subset, na.action, exclude = c(NA, NaN), drop.unused.levels = FALSE)
:
Author(s)
Michael Lawrence
See Also
-
by
in the base package. -
na.omit
in the stats package. -
transform
in the base package. -
xtabs
in the stats package. -
splitAsList
in this package (S4Vectors). -
SplitDataFrameList objects in the IRanges package.
-
DataFrame objects.
Examples
## split
sw <- DataFrame(swiss)
swsplit <- split(sw, sw[["Education"]])
## rbind & cbind
do.call(rbind, as.list(swsplit))
cbind(DataFrame(score), DataFrame(counts))
df <- DataFrame(as.data.frame(UCBAdmissions))
xtabs(Freq ~ Gender + Admit, df)