python数组符号速记：“ k％parents.shape [0]”是什么意思？

Question

我今天遇到这种表示法 本教程在这里：https://towardsdatascience.com/genetic-algorithm-implementation-in-python-5ab67bb124a6

parent1_idx = k%parents.shape[0]

右侧将返回什么？ 这种表达的名字是什么？ 预先感谢！

Answer 1

%是python中的运算符，即Modulus operator - it gives remainder of the division of left operand by the right

Answer 2

我在提到的文章的这段代码中看到了这一行：

for k in range(offspring_size[0]):
     # Index of the first parent to mate.
     parent1_idx = k%parents.shape[0]
     # Index of the second parent to mate.
     parent2_idx = (k+1)%parents.shape[0]

parents的定义如下：

parents = numpy.empty((num_parents, pop.shape[1]))
for parent_num in range(num_parents):
    max_fitness_idx = numpy.where(fitness == numpy.max(fitness))
    max_fitness_idx = max_fitness_idx[0][0]
    parents[parent_num, :] = pop[max_fitness_idx, :]
    fitness[max_fitness_idx] = -99999999999
return parents

从以上两行可以很明显地看出k和parents.shape[0]都是整数，因此这行是两个数值变量之间的简单modulo operator：a = b % c 。