# cf.DomainAncillary.equals¶

DomainAncillary.equals(other, rtol=None, atol=None, verbose=None, ignore_data_type=False, ignore_fill_value=False, ignore_properties=(), ignore_compression=False, ignore_type=False)[source]

Whether two instances are the same.

Equality is strict by default. This means that:

• the same descriptive properties must be present, with the same values and data types, and vector-valued properties must also have same the size and be element-wise equal (see the ignore_properties and ignore_data_type parameters), and

• if there are data arrays then they must have same shape and data type, the same missing data mask, and be element-wise equal (see the ignore_data_type parameter).

Two real numbers x and y are considered equal if |x-y|<=atol+rtol|y|, where atol (the tolerance on absolute differences) and rtol (the tolerance on relative differences) are positive, typically very small numbers. See the atol and rtol parameters.

If data arrays are compressed then the compression type and the underlying compressed arrays must be the same, as well as the arrays in their uncompressed forms. See the ignore_compression parameter.

Any type of object may be tested but, in general, equality is only possible with another object of the same type, or a subclass of one. See the ignore_type parameter.

NetCDF elements, such as netCDF variable and dimension names, do not constitute part of the CF data model and so are not checked.

New in version 1.7.0.

Parameters
other:

The object to compare for equality.

atol: float, optional

The tolerance on absolute differences between real numbers. The default value is set by the cf.ATOL function.

rtol: float, optional

The tolerance on relative differences between real numbers. The default value is set by the cf.RTOL function.

ignore_fill_value: bool, optional

If True then the “_FillValue” and “missing_value” properties are omitted from the comparison.

verbose: int or None, optional

If an integer from 0 to 3, corresponding to increasing verbosity (else -1 as a special case of maximal and extreme verbosity), set for the duration of the method call (only) as the minimum severity level cut-off of displayed log messages, regardless of the global configured cf.LOG_LEVEL.

Else, if None (the default value), log messages will be filtered out, or otherwise, according to the value of the cf.LOG_LEVEL setting.

Overall, the higher a non-negative integer that is set (up to a maximum of 3) the more description that is printed to convey information about differences that lead to inequality.

ignore_properties: sequence of str, optional

The names of properties to omit from the comparison.

ignore_data_type: bool, optional

If True then ignore the data types in all numerical comparisons. By default different numerical data types imply inequality, regardless of whether the elements are within the tolerance for equality.

ignore_compression: bool, optional

If True then any compression applied to the underlying arrays is ignored and only the uncompressed arrays are tested for equality. By default the compression type and, if appliciable, the underlying compressed arrays must be the same, as well as the arrays in their uncompressed forms.

ignore_type: bool, optional

Any type of object may be tested but, in general, equality is only possible with another object of the same type, or a subclass of one. If ignore_type is True then equality is possible for any object with a compatible API.

Returns
bool

Whether the two instances are equal.

Examples:

>>> f.equals(f)
True
>>> f.equals(f.copy())
True
>>> f.equals('a string')
False
>>> f.equals(f - 1)
False