CFLabel: CF label object

In ncdfCF: Easy Access to NetCDF Files with CF Metadata Conventions

CF label object

Description

This class represent CF labels, i.e. a variable of character type that provides a textual label for a discrete or general numeric axis. See also CFAxisCharacter, which is an axis with character labels.

Super classes

ncdfCF::CFObject -> ncdfCF::CFData -> CFLabel

Active bindings

friendlyClassName

(read-only) A nice description of the class.

values

Set or retrieve the labels of this object. In general you should use the coordinates field rather than this one. Upon setting values, if there is a linked netCDF resource, this object will be detached from it.

coordinates

(read-only) Retrieve the labels of this object. Upon retrieval, label values are read from the netCDF resource, if there is one, upon first access and cached thereafter.

length

(read-only) The number of labels in the set.

dimid

The netCDF dimension id of this label set. Setting this value to anything other than the correct value will lead to disaster.

Methods

Public methods

• CFLabel$new()

• CFLabel$print()

• CFLabel$identical()

• CFLabel$copy()

• CFLabel$slice()

• CFLabel$subset()

• CFLabel$write()

Inherited methods

• ncdfCF::CFObject$append_attribute()
• ncdfCF::CFObject$attach_to_group()
• ncdfCF::CFObject$attribute()
• ncdfCF::CFObject$attributes_identical()
• ncdfCF::CFObject$delete_attribute()
• ncdfCF::CFObject$print_attributes()
• ncdfCF::CFObject$set_attribute()
• ncdfCF::CFObject$write_attributes()
• ncdfCF::CFData$detach()
• ncdfCF::CFData$dim()

---

Method new()

Create a new instance of this class.

Usage

CFLabel$new(var, group, values = NA, start = NA, count = NA)

Arguments

var

The NCVariable instance upon which this CF object is based when read from a netCDF resource, or the name for the object new CF object to be created.

group

The CFGroup that this instance will live in.

values

Optional. The labels of the CF object. Ignored when argument var is a NCVariable object.

start

Optional. Integer index value indicating where to start reading data from the file. The value may be NA (default) to read all data, otherwise it must not be larger than the number of labels. Ignored when argument var is not an NCVariable instance.

count

Optional. Integer value indicating the number of labels to read from file. The value may be NA to read to the end of the labels, otherwise its value must agree with the corresponding start value and the number of labels on file. Ignored when argument var is not an NCVariable instance.

Returns

A CFLabel instance.

---

Method print()

Prints a summary of the labels to the console.

Usage

CFLabel$print(...)

Arguments

...

Arguments passed on to other functions. Of particular interest is ⁠width = ⁠ to indicate a maximum width of attribute columns.

---

Method identical()

Tests if the object passed to this method is identical to self.

Usage

CFLabel$identical(lbl)

Arguments

lbl

The CFLabel instance to test.

Returns

TRUE if the two label sets are identical, FALSE if not.

---

Method copy()

Create a copy of this label set. The copy is completely separate from self, meaning that both self and all of its components are made from new instances.

Usage

CFLabel$copy(name = "", group)

Arguments

name

The name for the new label set. If an empty string is passed, will use the name of this label set.

group

The CFGroup where the copy of this axis will live.

Returns

The newly created label set.

---

Method slice()

Given a range of domain coordinate values, returns the indices into the axis that fall within the supplied range.

Usage

CFLabel$slice(rng)

Arguments

rng

A character vector whose extreme (alphabetic) values indicate the indices of coordinates to return.

Returns

An integer vector of length 2 with the lower and higher indices into the axis that fall within the range of coordinates in argument rng. Returns NULL if no values of the axis fall within the range of coordinates.

---

Method subset()

Retrieve a subset of the labels.

Usage

CFLabel$subset(name, group, rng)

Arguments

name

The name for the new label set, optional.

group

The CFGroup where the copy of this label set will live.

rng

The range of indices whose values from this axis to include in the returned axis.

Returns

A CFLabel instance, or NULL if the rng values are invalid.

---

Method write()

Write the labels to a netCDF file, including its attributes.

Usage

CFLabel$write()

Returns

Self, invisibly.

ncdfCF documentation built on Jan. 24, 2026, 1:08 a.m.