cf.Index.log

Index.log(base=None, inplace=False, i=False)[source]

The logarithm of the data array.

By default the natural logarithm is taken, but any base may be specified.

The “standard_name” and “long_name” properties are removed from the result.

See also

exp

Parameters:
base: number, optional

The base of the logiarthm. By default a natural logiarithm is taken.

inplace: bool, optional

If True then do the operation in-place and return None.

i: deprecated at version 3.0.0

Use inplace parameter instead.
Returns:

The construct with the logarithm of data values.

Examples:

>>> f.data
<CF Data(1, 2): [[1, 2]]>
>>> f.log().data
<CF Data(1, 2): [[0.0, 0.69314718056]] ln(re 1)>

>>> f.data
<CF Data(1, 2): [[1, 2]] 2>
>>> f.log().data
<CF Data(1, 2): [[0.0, 0.69314718056]] ln(re 2 1)>

>>> f.data
<CF Data(1, 2): [[1, 2]] kg s-1 m-2>
>>> f.log().data
<CF Data(1, 2): [[0.0, 0.69314718056]] ln(re 1 m-2.kg.s-1)>

>>> f.log(inplace=True)
>>> f.Units
<Units: >
>>> f.log()
ValueError: Can't take the logarithm to the base 2.718281828459045 of <Units: >