genTable
Generic Tables and Data Frames of Descriptive Statistics
genTable
creates a table of arbitrary summaries conditional on
given values of independent variables given by a formula.
Aggregate
does the same, but returns a data.frame
instead.
fapply
is a generic function that dispatches on its data
argument. It is called internally by Aggregate
and genTable
.
Methods for this function can be used to adapt Aggregate
and
genTable
to data sources other than data frames.
- Keywords
- misc
Usage
Aggregate(formula, data=parent.frame(), subset=NULL,
names=NULL, addFreq=TRUE, drop = TRUE, as.vars=1,
…)genTable(formula, data=parent.frame(), subset=NULL,
names=NULL, addFreq=TRUE,…)
Arguments
- formula
a formula. The right hand side includes one or more grouping variables separated by '+'. These may be factors, numeric, or character vectors. The left hand side may be empty, a numerical variable, a factor, or an expression. See details below.
- data
an environment or data frame or an object coercable into a data frame.
- subset
an optional vector specifying a subset of observations to be used.
- names
an optional character vector giving names to the result(s) yielded by the expression on the left hand side of
formula
. This argument may be redundant if the left hand side results in is a named vector. (See the example below.)- addFreq
a logical value. If
TRUE
anddata
is a table or a data frame with a variable named "Freq", a call totable
,Table
,percent
, ornvalid
is supplied by an additional argumentFreq
and a call totable
is translated into a call toTable
.- drop
a logical value. If
TRUE
, empty groups (i.e. when there are no observations in the aggregated data frame that contain the defining combination of values or factor levels of the conditioning variables inby
) are dropped from the result ofAggregate
. Otherwise, result are filled withNA
, where appropriate.- as.vars
an integer; relevant only if the left hand side of the formula returns an array or a matrix - which dimension (rows, columns, or layers etc.) will transformed to variables? Defaults to columns in case of matrices and to the highest dimensional extend in case of arrays.
- …
further arguments, passed to methods or ignored.
Details
If an expression is given as left hand side of the formula, its
value is computed for any combination of values of the values on the
right hand side. If the right hand side is a dot, then all
variables in data
are added to the right hand side of the
formula.
If no expression is given as left hand side, then the frequency counts for the respective value combinations of the right hand variables are computed.
If a single factor is on the left hand side, then the left hand side is
translated into an appropriate
call to table()
. Note that also in this case addFreq
takes effect.
If a single numeric variable is on the left hand side, frequency
counts weighted by this variable are computed. In these cases,
genTable
is equivalent to xtabs
and
Aggregate
is equivalent to as.data.frame(xtabs(…))
.
Value
Aggregate
results in a data frame with conditional summaries and unique value combinations
of conditioning variables.
genTable
returns a table, that is, an array with class "table"
.
See Also
Examples
# NOT RUN {
ex.data <- expand.grid(mu=c(0,100),sigma=c(1,10))[rep(1:4,rep(100,4)),]
ex.data <- within(ex.data,
x<-rnorm(
n=nrow(ex.data),
mean=mu,
sd=sigma
)
)
Aggregate(~mu+sigma,data=ex.data)
Aggregate(mean(x)~mu+sigma,data=ex.data)
Aggregate(mean(x)~mu+sigma,data=ex.data,name="Average")
Aggregate(c(mean(x),sd(x))~mu+sigma,data=ex.data)
Aggregate(c(Mean=mean(x),StDev=sd(x),N=length(x))~mu+sigma,data=ex.data)
genTable(c(Mean=mean(x),StDev=sd(x),N=length(x))~mu+sigma,data=ex.data)
Aggregate(table(Admit)~.,data=UCBAdmissions)
Aggregate(Table(Admit,Freq)~.,data=UCBAdmissions)
Aggregate(Admit~.,data=UCBAdmissions)
Aggregate(percent(Admit)~.,data=UCBAdmissions)
Aggregate(percent(Admit)~Gender,data=UCBAdmissions)
Aggregate(percent(Admit)~Dept,data=UCBAdmissions)
Aggregate(percent(Gender)~Dept,data=UCBAdmissions)
Aggregate(percent(Admit)~Dept,data=UCBAdmissions,Gender=="Female")
genTable(percent(Admit)~Dept,data=UCBAdmissions,Gender=="Female")
# }