On Fri, Mar 6, 2009 at 2:19 AM, mattia <ger...@gmail.com> wrote:
> Hi, I'm new to python, and as the title says, can I improve this snippet
> (readability, speed, tricks):
>
> def get_fitness_and_population(fitness, population):
> return [(fitness(x), x) for x in population]
>
> def selection(fitness, population):
> '''
> Select the parent chromosomes from a population according to their
> fitness (the better fitness, the bigger chance to be selected)
> '''
> selected_population = []
> fap = get_fitness_and_population(fitness, population)
> pop_len = len(population)
> # elitism (it prevents a loss of the best found solution)
> # take the only 2 best solutions
> elite_population = sorted(fap)
> selected_population += [elite_population[pop_len-1][1]] +
> [elite_population[pop_len-2][1]]
> # go on with the rest of the elements
> for i in range(pop_len-2):
> # do something
Removing the unnecessary use of sorted() and using list.pop() rather
than explicit indices:
def selection(fitness, population):
'''
Select the parent chromosomes from a population according to their
fitness (the better fitness, the bigger chance to be selected)
'''
fap = get_fitness_and_population(fitness, population)
fap.sort()
# elitism (it prevents a loss of the best found solution)
# take the only 2 best solutions
selected_population = [fap.pop()[1] for i in range(2)]
# go on with the rest of the elements
for fit, pop in fap:
#do something
Cheers,
Chris
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http://blog.rebertia.com
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