array.len: Get the length of the array in an array column

In PivotalR: A Fast, Easy-to-Use Tool for Manipulating Tables in Databases and a Wrapper of MADlib

Description

The column of a table in database can be an array. This function measures the length of the array.

Usage

array.len(x)

Arguments

x	A db.obj object.

Value

An integer, which is the length of the array.

Author(s)

Author: Predictive Analytics Team at Pivotal Inc.

Maintainer: Frank McQuillan, Pivotal Inc. [e-mail]

See Also

db.array combines columns of a table/view into an array.

as.list expands the db.obj columns into a list of separated db.Rquery objects.

cbind2 and cbind combine multiple db.obj objects into one db.obj object.

Examples

## 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)

delete("abalone", conn.id = cid)
x <- as.db.data.frame(abalone, "abalone", conn.id = cid, verbose = FALSE)
y <- db.array(x[-2]) # put columns into an array
names(y) # "agg_opr"
array.len(y$agg_opr) # 9

db.disconnect(cid, verbose = FALSE)

## End(Not run)

PivotalR documentation built on March 13, 2021, 1:06 a.m.