Get a CF object from a data set

This method can be used to retrieve a variable or axis from the data set by name.

Usage

# S3 method for class 'CFDataset'
x[[i]]

Arguments

x

An CFDataset to extract a variable or axis from.

i

The name of a variable or axis in x. If data set x has groups, i should be an absolute path to the object to retrieve.

Value

An instance of CFVariable or an CFAxis descendant class, or NULL if the name is not found.

Details

If the data set has groups, the name i of the variable or axis should be fully qualified with the path to the group where the object is located. This fully qualified name can be retrieved with the names() and dimnames() functions, respectively.

Examples

fn <- system.file("extdata", "ERA5land_Rwanda_20160101.nc", package = "ncdfCF")
ds <- open_ncdf(fn)
v1 <- ds$var_names[1]
var <- ds[[v1]]
var
#> <Variable> t2m 
#> Long name: 2 metre temperature 
#> 
#> Values: (not loaded)
#> 
#> Axes:
#>  axis name      length values                                       
#>  X    longitude 31     [28 ... 31]                                  
#>  Y    latitude  21     [-1 ... -3]                                  
#>  T    time      24-U   [2016-01-01T00:00:00 ... 2016-01-01T23:00:00]
#>  unit                             
#>  degrees_east                     
#>  degrees_north                    
#>  hours since 1900-01-01 00:00:00.0
#> 
#> Attributes:
#>  name      type    length value              
#>  long_name NC_CHAR 19     2 metre temperature
#>  units     NC_CHAR  1     K