# cfdm.CoordinateReference.equals¶

CoordinateReference.equals(other, rtol=None, atol=None, verbose=None, ignore_type=False)[source]

Whether two coordinate reference constructs are the same.

Equality is strict by default. This means that:

• the datum and coordinate conversion components must have the same string and numerical parameters.

The dimension coordinate, auxiliary coordinate and domain ancillary constructs of the coordinate reference constructs are not considered, because they may only be correctly interpreted by the field constructs that contain the coordinate reference constructs in question. They are, however, taken into account when two fields constructs are tested for equality.

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.

Any type of object may be tested but, in general, equality is only possible with another coordinate reference construct, 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 (cfdm): 1.7.0

Parameters
other:

The object to compare for equality.

atol: number, optional

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

rtol: number, optional

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

verbose: int or str or None, optional

If an integer from -1 to 3, or an equivalent string equal ignoring case to one of:

• 'DISABLE' (0)

• 'WARNING' (1)

• 'INFO' (2)

• 'DETAIL' (3)

• 'DEBUG' (-1)

set for the duration of the method call only as the minimum cut-off for the verboseness level of displayed output (log) messages, regardless of the globally-configured cfdm.log_level. Note that increasing numerical value corresponds to increasing verbosity, with the exception of -1 as a special case of maximal and extreme verbosity.

Otherwise, if None (the default value), output messages will be shown according to the value of the cfdm.log_level setting.

Overall, the higher a non-negative integer or equivalent string that is set (up to a maximum of 3/'DETAIL') for increasing verbosity, the more description that is printed to convey information about the operation.

ignore_type: bool, optional

Any type of object may be tested but, in general, equality is only possible with another CoordinateReference instance, or a subclass of one. If ignore_type is True then cfdm.CoordinateReference(source=other) is tested, rather than the other defined by the other parameter.

Returns
bool

Whether the two coordinate reference constructs are equal.

Examples:

>>> c = cfdm.CoordinateReference(
...     coordinates=['dimensioncoordinate0']
... )
>>> c.equals(c)
True
>>> c.equals(c.copy())
True
>>> c.equals('not a coordinate reference')
False