# Customise the selection process¶

You can alter the selection discipline of the EA using two parameters in edo.DataOptimiser: best_prop and lucky_prop. These control how many of the best individuals and any lucky (random) individuals should be selected respectively.

For example, say we wanted to see the effect of selecting parents purely at random in each generation. Then we would set best_prop to be zero, and lucky_prop to be some value between 0 and 1:

>>> import edo
>>> from edo.distributions import Uniform
>>>
>>> def xsquared(ind):
...     return ind.dataframe.iloc[0, 0] ** 2
>>>
>>> opt = edo.DataOptimiser(
...     xsquared,
...     100,
...     [1, 1],
...     [1, 1],
...     [edo.Family(Uniform)],
...     best_prop=0,
...     lucky_prop=0.25,
... )