merge.Lexis {Epi} | R Documentation |
Merge additional variables from a data frame into a Lexis object.
## S3 method for class 'Lexis': merge(x, y, id, by, ...)
x |
an object of class Lexis |
y |
a data frame |
id |
the name of the variable in y to use for matching
against the variable lex.id in x .
|
by |
if matching is not done by id, a vector of variable names
common to both x and y |
... |
optional arguments to be passed to merge.data.frame |
A Lexis
object can be considered as an augmented data frame
in which some variables are time-dependent variables representing
follow-up. The Lexis
function produces a minimal object
containing only these time-dependent variables. Additional variables
may be added to a Lexis
object using the merge
method.
A Lexis
object with additional columns taken from the
merged data frame.
The variable given as the by.y
argument must not contain
any duplicate values in the data frame y
.
Martyn Plummer
merge.data.frame
, subset.Lexis