Edit an element of an oce object, inserting a note in the processing log of the returned object.
oceEdit(
x,
item,
value,
action,
reason = "",
person = "",
debug = getOption("oceDebug")
)
A oce object, altered appropriately, and with a log item indicating the nature of the alteration.
an oce object. The exact action of oceEdit()
depends
on the sub-class of x
.
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.
new value for item
, if both supplied.
optional character string containing R code to carry out some action on the object.
character string giving the reason for the change.
character string giving the name of person making the change.
an integer that specifies a level of debugging, with 0 or less indicating no debugging, and 1 or more indicating debugging.
Dan Kelley
There are several ways to use this function.
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.
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
, as in Example 2.
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.
library(oce)
data(ctd)
# Example 1: change latitude
ctd2 <- oceEdit(ctd, item="latitude", value=47.8879,
reason="illustration", person="Dan Kelley")
# Example 2: add 0.1 dbar to pressure
ctd3 <- oceEdit(ctd,action="x@data$pressure<-x@data$pressure+0.1")
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