從python 2.7的列表中刪除每個第n個元素

Question

我已經被賦予創建代碼的任務。任務如下：

You are the captain of a sailing vessel and you and your crew have been captured by pirates. The pirate captain has all of you standing in a circle on the deck of his ship trying to decide in which order you should walk the plank. Eventually he decides on the following method:

(a) The pirate captain asks you to pick a number N.

(b) The first person to walk the plank will be the Nth person (starting from you).

(c) The captain will then continue around the circle forcing every Nth person to walk the plank.

(d) Once there is only one person left, that person will be given freedom.

For example: The crew consists of: Andrew, Brenda, Craig, Deidre, Edward, Felicity, Greg and Harriet. Andrew selects N=2. The crew will walk the plank in the order: Brenda, Deidre, Felicity, Harriet, Craig, Greg, Edward. Andrew will be given freedom.

代碼中，我至今是：

def survivor(names, step): 
    names = ["Andrew", "Brenda", "Craig", "Deidre", "Edward", "Felicity", "Greg", "Harriet"] 
    Next = step - 1 
    names.pop(Next) 
    print names 

這將從列表中刪除第n次的人，但我不知道如何通過列表循環繼續移除第n個人。

我需要它，所以讓我們假設step = 3，然後我需要它刪除craig，然後從craig開始計數，並刪除下一個第三個元素，這是幸福等等，直到有一個人離開。

我該怎麼做？

Answer 1

這似乎工作：

from collections import deque 
def survivor(names, step):  
    circle = deque(names) 
    while len(circle) > 1: 
     circle.rotate(1-step) 
     print circle.popleft() 
    return circle[0] 

它打印海盜的受害者的姓名，並返回倖存者的名字：

In [17]: crew = ["Andrew", "Brenda", "Craig", "Deidre", 
    ....: "Edward", "Felicity", "Greg", "Harriet"] 

In [18]: survivor(crew, 2) 
Brenda 
Deidre 
Felicity 
Harriet 
Craig 
Greg 
Edward 
Out[18]: 'Andrew' 

In [19]: survivor(crew, 3) 
Craig 
Felicity 
Andrew 
Edward 
Brenda 
Harriet 
Deidre 
Out[19]: 'Greg' 

Answer 2

下面的代碼應該做的，你問的一切，包括執行safeN功能：

import collections 
import itertools 

def walk_plank(names, N): 
    "Walk everyone down the plank." 
    circle = collections.deque(names) 
    while circle: 
     circle.rotate(-N) 
     yield circle.pop() 

def save_last(names, N): 
    "Save the last person from walking the plank." 
    for name in walk_plank(names, N): 
     pass 
    return name 

def safeN(names, name): 
    "Find the best N to save someone from walking the plank." 
    assert name in names, 'Name must be in names!' 
    for N in itertools.count(1): 
     if save_last(names, N) == name: 
      return N 

編輯：以上是在Windows中使用IDLE時上述代碼的一些示例用法。

Python 3.3.0 (v3.3.0:bd8afb90ebf2, Sep 29 2012, 10:55:48) [MSC v.1600 32 bit (Intel)] on win32 
Type "copyright", "credits" or "license()" for more information. 
>>> import collections, itertools 
>>> def walk_plank(names, N): 
     "Walk everyone down the plank." 
     circle = collections.deque(names) 
     while circle: 
      circle.rotate(-N) 
      yield circle.pop() 

>>> def save_last(names, N): 
     "Save the last person from walking the plank." 
     for name in walk_plank(names, N): 
      pass 
     return name 

>>> def safeN(names, name): 
     "Find the best N to save someone from walking the plank." 
     assert name in names, 'Name must be in names!' 
     for N in itertools.count(1): 
      if save_last(names, N) == name: 
       return N 

>>> names = 'Andrew Brenda Craig Deidre Edward Felicity Greg Harriet'.split() 
>>> tuple(walk_plank(names, 2)) 
('Brenda', 'Deidre', 'Felicity', 'Harriet', 'Craig', 'Greg', 'Edward', 'Andrew') 
>>> save_last(names, 2) 
'Andrew' 
>>> safeN(names, 'Andrew') 
2 
>>> safeN(names, 'Brenda') 
19 
>>> save_last(names, 19) 
'Brenda' 
>>> tuple(walk_plank(names, 19)) 
('Craig', 'Harriet', 'Andrew', 'Felicity', 'Deidre', 'Edward', 'Greg', 'Brenda') 
>>>