cbind2-methods {PivotalR} | R Documentation |
db.obj
Objects by Columnscbind2
or cbind
combine two or multiple db.obj
objects to form a new db.obj
. And as.list
does the opposite and expand a db.obj
object into a list of db.obj
objects with each one of them representing one column of the original db.obj
object. as.list
is usually used together with Reduce
and Map
.
## S4 method for signature 'db.obj,db.obj' cbind2(x, y) ## S4 method for signature 'db.obj' as.list(x, array = FALSE, ...)
x, y |
The signature of the method. Both arguments are |
array |
logical, default is |
... |
In |
cbind2
or cbind
: A db.Rquery
object, which contains all columns of
x and y.
as.list
: A list of db.Rquery
objects, which are the columns of x
Author: Predictive Analytics Team at Pivotal Inc.
Maintainer: Frank McQuillan, Pivotal Inc. fmcquillan@pivotal.io
db.array
combines columns of a table/view into an
array.
array.len
measures the length of the array in an array column.
## Not run: ## set up the database connection ## Assume that .port is port number and .dbname is the database name cid <- db.connect(port = .port, dbname = .dbname, verbose = FALSE) ## create a table from the example data.frame "abalone" delete('abalone', conn.id = cid) x <- as.db.data.frame(abalone, 'abalone', conn.id = cid, verbose = FALSE) fit <- madlib.lm(rings ~ . - id - sex, data = x) ## create a db.Rquery object that has two columns z <- cbind(x$rings, predict(fit, x)) ## plot prediction v.s. real value plot(lookat(z, 100)) ## expand the db.obj unlist(Map(function(x) if (col.types(x) == "text") paste(lk(unique(x)), collapse="-", sep="") else lk(mean(x))), as.list(x)) ## sum of all columns (excluding the 2nd column) Reduce(function(left, right) left + right, as.list(x[-2])) db.disconnect(cid, verbose = FALSE) ## End(Not run)