pdata.frame {plm} | R Documentation |
a data.frame
with further attributes useful for panel data
pdata.frame(x,id,time=NULL,name=NULL) ## S3 method for class 'pdata.frame': summary(object,...) ## S3 method for class 'summary.pdata.frame': print(x,...)
x |
a data.frame (a pdata.frame for the print
and summary methods), |
object |
a pdata.frame object, |
id |
the individual index, |
time |
the time index, |
name |
the name of the pdata.frame (the name of x if NULL ), |
... |
further arguments. |
id
and time
can be the names of the
indexes contained in the data.frame
if any. time
may be
omitted, in this case a new variable called "time"
is added to
the data.frame
. For balanced panels, the argument id
can
be an integer. In this case, two new variables, "time"
and
"id"
are added to the data.frame
.
pdata.frame
calls pdim
to check for the individual and
time dimensions of the panel and pvar
to check for the
individual and time variation of each variable.
All elements of a pdata.frame
are of class pserie
and have
an attribute data
which is the name of the pdata.frame
.
The print
method is inherited from data.frame
. A
summary
method is provided which add to the
summary.data.frame
method informations about the structure of the
panel.
A as.data.frame
method is also provided to coerce a
pdata.frame
to an ordinary data.frame
. Finally, a
pfix
function is available to edit a pdata.frame
. It
mimics the behavior of fix
(which is not a generic
function). Only editing is possible, not modification.
This function returns internally an object of class c("pdata.frame","data.frame")
, which is a
data.frame
with three additional attributes :
indexes |
a list containing the names of the
individual (id ) and time (time ) index variables, |
pdim |
a list containing the dimension of the pdata.frame (see pdim ), |
pvar |
a list of two logical vectors indicating whether each
variable varies across individuals (id.var ) and
across time periods (time.var ) (see pvar ). |
Yves Croissant
pdim
, pvar
, pread.table
.
library(Ecdat) #There are 595 individuals data(Wages) pdata.frame(Wages,595) # Gasoline contains two variables which are individual and time indexes # The pdata.frame is called gas data(Gasoline) pdata.frame(Gasoline,"country","year",name="gas") summary(gas) # Hedonic is an unbalanced panel, townid is the individual index data(Hedonic) pdata.frame(Hedonic,"townid")