最受欢迎的乐队Python

Question

你好，我有一个问题，我必须采取一个名单，并在这些名单中找到个别乐队，看看他们是否都有一个共同的最喜欢的乐队。如果是这样，我应该输出true。我需要遵循这种编程方法，将代码模块化，但我似乎无法获得它。这是我目前的代码。谢谢你所能给予的一切帮助。你知道吗

favoriteBandLists = [["Metallica","Linkin Park","Alice In Chains","Nirvana", "Soundgarden"],
    ["Pink Floyd","Alice In Chains","Soundgarden","Metallica","Linkin Park"],
    ["Audioslave","Offspring","The Beatles", "Soundgarden"]]

def commonFavoriteBand(favoriteBandLists):

    thereExists= False
    for i in (favoriteBandLists[2]):
        if(commonFavoriteBandA(favoriteBandLists)):
            thereExists = True
    return (thereExists)

def commonFavoriteBandA(favoriteBandLists):

    foundCounterExampleYet = False
    for band in favoriteBandLists[2]:
        if not(band == favoriteBandLists[0:1]):
            foundCounterExampleYet = True
    return not foundCounterExampleYet

print(commonFavoriteBand(favoriteBandLists))

Answer 1

如果你真的想写一些东西来显示你正在模块化你的代码，首先做一个函数，返回两个列表中的公共元素：

def commonBand(L1, L2):
    answer = []
    for band in L1:
        if band in L2:
            answer.append(band)
    return answer

现在，反复多次调用该函数：

def main(listOfLists):
    i = 1
    answer = listOfLists[0]
    while i<len(listOfLists):
        answer = commonBand(answer, listOfLists[i])
        if not answer:
            break
        i += 1
    return answer

输出：

In [193]: main(favoriteBandLists)
Out[193]: ['Soundgarden']

注意：这对我来说像是一个家庭作业问题，所以我的代码有助于解决这个问题。否则的话，我会使用集合交集方法，这在这里的其他回答中已经讨论过了

Answer 2

使用来自set对象的intersect

set(["Metallica","Linkin Park","Alice In Chains","Nirvana", "Soundgarden"]).intersection(["Pink Floyd","Alice In Chains","Soundgarden","Metallica","Linkin Park"])
set(['Linkin Park', 'Alice In Chains', 'Soundgarden', 'Metallica'])

编辑

如果需要遍历列表，可以使用任何列表遍历函数，如map、filter或reduce。你知道吗

favoriteBandLists = [["Metallica","Linkin Park","Alice In Chains","Nirvana", "Soundgarden"],
    ["Pink Floyd","Alice In Chains","Soundgarden","Metallica","Linkin Park"],
    ["Audioslave","Offspring","The Beatles", "Soundgarden"]]
reduce(lambda a, b: a.intersection(b), (set(a) for a in favoriteBandLists))
set(['Soundgarden'])