CFData: CF data object

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

CF data object

Description

This class is a basic ancestor to all classes that contain data from a netCDF resource, specifically data variables and axes. More useful classes use this class as ancestor.

Super class

ncdfCF::CFObject -> CFData

Active bindings

data_type

Set or retrieve the data type of the data in the object. Setting the data type to a wrong value can have unpredictable and mostly catastrophic consequences.

ndims

(read-only) Retrieve the dimensionality of the data in the array.

NC_map

Returns a list with columns "start" and "count" giving the indices for reading the data of this object from a netCDF resource. The list is empty if this object is not backed by a netCDF resource.

Methods

Public methods

• CFData$new()

• CFData$detach()

• CFData$dim()

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()

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Method new()

Create a new CFData instance. This method is called upon creating CF objects, such as when opening a netCDF resource or creating a new CF object. It is rarely, if ever, useful to call this constructor directly. Instead, use the methods from higher-level classes such as CFVariable.

Usage

CFData$new(
  obj,
  group,
  values,
  start = 1L,
  count = NA,
  attributes = data.frame()
)

Arguments

obj

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

group

The CFGroup that this instance will live in.

values

Optional. The values of the object in an array. Ignored when argument obj is an NCVariable instance.

start

Optional. Vector of indices where to start reading data along the dimensions of the array on file. The vector must be NA to read all data, otherwise it must have agree with the dimensions of the array on file. Default value is 1, i.e. start from the beginning of the 1-D NC variable. Ignored when argument obj is not an NCVariable instance.

count

Optional. Vector of number of elements to read along each dimension of the array on file. The vector must be NA to read to the end of each dimension, otherwise its value must agree with the corresponding start value and the dimension of the array on file. Default is NA. Ignored when argument obj is not an NCVariable instance.

attributes

Optional. A data.frame with the attributes of the object.

Returns

A CFData instance.

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Method detach()

Detach the current object from its underlying netCDF resource. If necessary, data is read from the resource before detaching.

Usage

CFData$detach()

---

Method dim()

Retrieve the dimensions of the data of this object.

Usage

CFData$dim(dimension)

Arguments

dimension

Optional. The index of the dimension to retrieve the length for. If omitted, retrieve the lengths of all dimensions.

Returns

Integer vector with the length of each requested dimension.

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