is.pseries: Check if an object is a pseries
In plm: Linear Models for Panel Data

Description Usage Arguments Details Value See Also Examples

This function checks if an object qualifies as a pseries

1	is.pseries(object)

object

object to be checked for pseries features

A "pseries" is a wrapper around a "basic class" (numeric, factor, logical, character, or complex).

To qualify as a pseries, an object needs to have the following features:

class contains "pseries" and there are at least two classes ("pseries" and the basic class),
have an appropriate index attribute (defines the panel structure),
any of is.numeric, is.factor, is.logical, is.character, is.complex is TRUE.

A logical indicating whether the object is a pseries (TRUE) or not (FALSE).

pseries() for some computations on pseries and some further links.

# Create a pdata.frame and extract a series, which becomes a pseries
data("EmplUK", package = "plm")
Em <- pdata.frame(EmplUK)
z <- Em$output

class(z) # pseries as indicated by class
is.pseries(z) # and confirmed by check

# destroy index of pseries and re-check
attr(z, "index") <- NA
is.pseries(z) # now FALSE