迭代时从Python中的列表中删除项目

Question

我正在为锦标赛应用编写循环算法.

当玩家数量为奇数时,我会添加'DELETE'到玩家列表中,但稍后,当我想要从包含的计划列表中删除所有项目时'DELETE',我不能 - 一个人总是离开.请看一下代码 - 问题很简单,我想这是关于列表的; 我只是看不到它.

"""
Round-robin tournament:
1, 2, 3, 4, | 5, 6, 7, 8    =>  1, 2, 3, 4  => rotate all but 1 =>  1, 5, 2, 3  => repeat =>    1, 6, 5, 2  ...
                    5, 6, 7, 8              6, 7, 8, 4          7, 8, 4, 3
in every round pick l1[0] and l2[0] as first couple, after that l1[1] and l2[1]...
"""

import math

lst = []
schedule = []
delLater = False

for i in range(3):                  #make list of numbers
    lst.append(i+1)

if len(lst) % 2 != 0:               #if num of items is odd, add 'DELETE'
    lst.append('DELETE')
    delLater = True


while len(schedule) < math.factorial(len(lst))/(2*math.factorial(len(lst) - 2)): #!(n)/!(n-k)

    mid = len(lst)/2

    l1 = lst[:mid]
    l2 = lst[mid:]

    for i in range(len(l1)):            
        schedule.append((l1[i], l2[i]))         #add lst items in schedule

    l1.insert(1, l2[0])             #rotate lst
    l2.append(l1[-1])
    lst = l1[:-1] + l2[1:]


if delLater == True:                #PROBLEM!!! One DELETE always left in list
    for x in schedule:
        if 'DELETE' in x:
            schedule.remove(x)

i = 1
for x in schedule:
    print i, x
    i+=1

Answer 1

schedule[:] = [x for x in schedule if 'DELETE' not in x]

查看有关在迭代时从列表中删除的其他问题.

Answer 2

您不应在迭代列表时修改列表：

for x in schedule:
    if 'DELETE' in x:
        schedule.remove(x)

相反，请尝试：

schedule[:] = [x for x in schedule if 'DELETE' not in x]

有关详细信息，请参阅如何在迭代时从列表中删除项目？