我正在尝试实现功能。它的工作方式应该是这样的：

它需要两个列表。

标记一些索引，最好居中。

父母双方都切换标记索引。

其他索引按顺序转到其父元素。

如果该父元素中已经存在相同的元素，则它将映射并检查同一元素在其他父元素的位置并到达那里。import random

def pm(indA, indB):

size = min(len(indA), len(indB))

c1, c2 = [0] * size, [0] * size

# Initialize the position of each indices in the individuals

for i in range(1,size):

c1[indA[i]] = i

c2[indB[i]] = i

crosspoint1 = random.randint(0, size)

crosspoint2 = random.randint(0, size - 1)

if crosspoint2 >= crosspoint1:

crosspoint2 += 1

else: # Swap the two cx points

crosspoint1, crosspointt2 = crosspoint2, crosspoint1

for i in range(crosspoint1, crosspoint2):

# Keep track of the selected values

temp1 = indA[i]

temp2 = indB[i]

# Swap the matched value

indA[i], indA[c1[temp2]] = temp2, temp1

indB[i], indB[c2[temp1]] = temp1, temp2

# Position bookkeeping

c1[temp1], c1[temp2] = c1[temp2], c1[temp1]

c2[temp1], c2[temp2] = c2[temp2], c2[temp1]

return indA, indB

a,b = pm([3, 4, 8, 2, 7, 1, 6, 5],[4, 2, 5, 1, 6, 8, 3, 7])

错误：

in pm

c1[indA[i]] = i

IndexError: list assignment index out of range

最佳答案

不知道您的代码中是否还有其他错误(我没有运行它)，但这是对此的解释。在Python(与其他大多数语言一样)中，列表(更精确的序列)索引基于0：>>> l = [1, 2, 3, 4, 5, 6]

>>>

>>> for e in l:

... print(e, l.index(e))

...

1 0

2 1

3 2

4 3

5 4

6 5

>>>

>>> l[0]

1

>>> l[5]

6

>>> l[6]

Traceback (most recent call last):

File "", line 1, in

IndexError: list index out of range

总结您的问题：

您的indA和indB列表各有6个元素([1..6])及其索引：[0..5]

您的c1和c2列表也有6个元素(索引也为[0..5])

但是，您使用的是＃1中的值。作为＃2列表中的索引，而值6是一个问题，因为没有这样的索引

要解决您的问题，您应该使用有效的索引值。要么：

在indA和indB中有适当的值(这是我选择的值)：

a, b = pmxCrossover([0, 3, 1, 2, 5, 4], [4, 0, 2, 3, 5, 1])

减去1，无论遇到indA或indB用作索引的值：

c1[indA[i] - 1] = i

作为一般建议：每当遇到错误时，请在出现故障的行之前添加打印语句(从中打印(部分)内容)，这可能会为您提供线索，从而可以自己解决问题。

@ EDIT0

发布原始代码(略有修改的版本)，并进行索引转换：

在算法之前：(从每个元素中减去1)具有有效索引

在算法之后：加1返回基于1的索引

code00.py：

#!/usr/bin/env python3

import sys

import random

def pmx_crossover(ind_a, ind_b):

size = min(len(ind_a), len(ind_b))

c1, c2 = [0] * size, [0] * size

# Initialize the position of each indices in the individuals

for i in range(1, size):

c1[ind_a[i]] = i

c2[ind_b[i]] = i

# Choose crossover points

crosspoint1 = random.randint(0, size)

crosspoint2 = random.randint(0, size - 1)

if crosspoint2 >= crosspoint1:

crosspoint2 += 1

else: # Swap the two cx points

crosspoint1, crosspointt2 = crosspoint2, crosspoint1

# Apply crossover between cx points

for i in range(crosspoint1, crosspoint2):

# Keep track of the selected values

temp1 = ind_a[i]

temp2 = ind_b[i]

# Swap the matched value

ind_a[i], ind_a[c1[temp2]] = temp2, temp1

ind_b[i], ind_b[c2[temp1]] = temp1, temp2

# Position bookkeeping

c1[temp1], c1[temp2] = c1[temp2], c1[temp1]

c2[temp1], c2[temp2] = c2[temp2], c2[temp1]

return ind_a, ind_b

def main():

#initial_a, initial_b = [1, 2, 3, 4, 5, 6, 7, 8], [3, 7, 5, 1, 6, 8, 2, 4]

initial_a, initial_b = [1, 4, 2, 3, 6, 5], [5, 1, 3, 4, 6, 2]

index_offset = 1

temp_a = [i - index_offset for i in initial_a]

temp_b = [i - index_offset for i in initial_b]

a, b = pmx_crossover(temp_a, temp_b)

final_a = [i + index_offset for i in a]

final_b = [i + index_offset for i in b]

print("Initial: {0:}, {1:}".format(initial_a, initial_b))

print("Final: {0:}, {1:}".format(final_a, final_b))

if __name__ == "__main__":

print("Python {0:s} {1:d}bit on {2:s}\n".format(" ".join(item.strip() for item in sys.version.split("\n")), 64 if sys.maxsize > 0x100000000 else 32, sys.platform))

main()

print("\nDone.")

输出(一种可能性(由于random.randint))：

[cfati@CFATI-5510-0:e:\Work\Dev\StackOverflow\q058424002]> "e:\Work\Dev\VEnvs\py_064_03.07.03_test0\Scripts\python.exe" code00.py

Python 3.7.3 (v3.7.3:ef4ec6ed12, Mar 25 2019, 22:22:05) [MSC v.1916 64 bit (AMD64)] 64bit on win32

Initial: [1, 4, 2, 3, 6, 5], [5, 1, 3, 4, 6, 2]

Final: [1, 3, 2, 4, 6, 5], [5, 1, 4, 3, 6, 2]

Done.