NumPy参考 >通用功能（ufunc） > numpy.ufunc.identity
attribute
ufunc.identity¶The identity value.
Data attribute containing the identity element for the ufunc, if it has one. If it does not, the attribute value is None.
Examples
>>> np.add.identity
0
>>> np.multiply.identity
1
>>> np.power.identity
1
>>> print(np.exp.identity)
None