class cf.Variable(properties={}, attributes=None, data=None, source=None, copy=True)[source]

Bases: object

Base class for storing a data array with metadata.

A variable contains a data array and metadata comprising properties to describe the physical nature of the data.

All components of a variable are optional.


properties: dict, optional

Initialize CF properties from the dictionary’s key/value pairs.

attributes: dict, optional

Provide attributes from the dictionary’s key/value pairs.

data: cf.Data, optional

Provide a data array.

source: cf.{+Variable}, optional

Take the attributes, CF properties and data array from the source {+variable}. Any attributes, CF properties or data array specified with other parameters are set after initialisation from the source {+variable}.

copy: bool, optional

If False then do not deep copy arguments prior to initialization. By default arguments are deep copied.

CF Properties

add_offset The add_offset CF property.
calendar The calendar CF property.
comment The comment CF property.
_FillValue The _FillValue CF property.
history The history CF property.
leap_month The leap_month CF property.
leap_year The leap_year CF property.
long_name The long_name CF property.
missing_value The missing_value CF property.
month_lengths The month_lengths CF property.
scale_factor The scale_factor CF property.
standard_name The standard_name CF property.
units The units CF property.
valid_max The valid_max CF property.
valid_min The valid_min CF property.
valid_range The valid_range CF property.


array A numpy array deep copy of the data array.
binary_mask A binary (0 and 1) missing data mask of the data array.
data The cf.Data object containing the data array.
day The day of each date-time data array element.
dtarray An independent numpy array of date-time objects.
dtype The numpy data type of the data array.
hour The hour of each date-time data array element.
hardmask Whether the mask is hard (True) or soft (False).
isscalar True if the data array is scalar.
mask The mask of the data array.
minute The minute of each date-time data array element.
month The month of each date-time data array element.
ndim The number of dimensions in the data array.
second The second of each date-time data array element.
shape A tuple of the data array’s dimension sizes.
size The number of elements in the data array.
subspace Return a new variable whose data is subspaced.
Units The cf.Units object containing the units of the data array.
varray A numpy array view of the data array.
year The year of each date-time data array element.


attributes Inspect or change attributes which are not CF properties.
chunk Partition the data array.
clip Limit the values in the data array.
close Close all files referenced by the variable.
copy Return a deep copy.
cos Take the trigonometric cosine of the data array.
datum Return an element of the data array as a standard Python scalar.
delprop Delete a CF property.
dump Return a string containing a full description of the instance.
equals True if two variables are equal, False otherwise.
expand_dims Insert a size 1 axis into the data array.
files Return the names of any files containing parts of the data array.
fill_value Return the data array missing data value.
flip Flip dimensions of the data array in place.
getprop Get a CF property.
hasprop Return True if a CF property exists, otherise False.
HDF_chunks Specify HDF5 chunks for the data array.
identity Return the identity of the variable.
insert_data Insert a new data array into the variable in place.
mask_invalid Mask the array where invalid values occur.
match Determine whether or not a variable satisfies conditions.
name Return a name for the variable.
override_units Override the units.
properties Inspect or change the CF properties.
select has been deprecated.
setprop Set a CF property.
sin The trigonometric sine of the data array.
squeeze Remove size 1 dimensions from the data array
transpose Permute the dimensions of the data array.
unique The unique elements of the data array.
where Set data array elements depending on a condition.