oce (version 1.0-1)

oceEdit: Edit an Oce Object

Description

Edit an element of an oce object, inserting a note in the processing log of the returned object.

Usage

oceEdit(x, item, value, action, reason = "", person = "",
  debug = getOption("oceDebug"))

Arguments

x

an oce object. The exact action of oceEdit depends on the class of x.

item

if supplied, a character string naming an item in the object's metadata or data slot, the former being checked first. An exception is if item starts with "data@" or "metadata@", in which case the named slot is updated with a changed value of the contents of item after the @ character.

value

new value for item, if both supplied.

action

optional character string containing R code to carry out some action on the object.

reason

character string giving the reason for the change.

person

character string giving the name of person making the change.

debug

an integer that specifies a level of debugging, with 0 or less indicating no debugging, and 1 or more indicating debugging.

Value

An object of class "oce", altered appropriately, and with a log item indicating the nature of the alteration.

Details

There are several ways to use this function.

• Case 1. If both an item and value are supplied, then either the object's metadata or data slot may be altered. There are two ways in which this can be done.

  • Case 1A. If the item string does not contain an @ character, then the metadata slot is examined for an entry named item, and that is modified if so. Alternatively, if item is found in metadata, then that value is modified. However, if item is not found in either metadata or data, then an error is reported (see 1B for how to add something that does not yet exist).

  • Case 1B. If the item string contains the @ character, then the text to the left of that character must be either "metadata" or "data", and it names the slot in which the change is done. In contrast with case 1A, this will create a new item, if it is not already in existence.

• Case 2. If item and value are not supplied, then action must be supplied. This is a character string specifying some action to be performed on the object, e.g. a manipulation of a column. The action must refer to the object as x; see Examples.

In any case, a log entry is stored in the object, to document the change. Indeed, this is the main benefit to using this function, instead of altering the object directly. The log entry will be most useful if it contains a brief note on the reason for the change, and the name of the person doing the work.

Examples

# NOT RUN {
library(oce)
data(ctd)
ctd2 <- oceEdit(ctd, item="latitude", value=47.8879,
               reason="illustration", person="Dan Kelley")
ctd3 <- oceEdit(ctd,action="x@data$pressure<-x@data$pressure-1")
# }