Question

def main():

    winners = []
    winnersND = []

    readData()
    noDuplicates(winners)


def readData():

    winners_file = open('WorldSeriesWinners.txt', 'r')

    winners = winners_file.readlines()

    winners_file.close()

    index = 0
    while index < len(winners):
            winners[index] = winners[index].rstrip('\n')
            index += 1

    print(winners)
    print()
    print()

    return winners


def noDuplicates(winners):

    winnersND = []

    for x in winners:
            if x not in winnersND:
                    winnersND.append(x)

    print (winnersND)

    winnersND = tuple(winnersND)

    return winnersND

main()

所以我一直在寻找各处，我已经经历了七个小时的代码迭代试图让这项工作，但由于某种原因，获奖者名单打印在readData()，但是winnersND列表（唯一和有序的获胜者列表元素列表）不会被打印，而是显示输出：[]。我很想澄清一下我在这里搞砸了什么。谢谢！

Answer 1

因为winners是main是一个空列表。您在winners中重新分配了名为readData()的变量并将其返回，但您没有捕获返回值。因此main继续将空winners列表传递给noDuplicates()。

尝试将main更改为：

def main():
    winners = readData()
    winnersND = noDuplicates(winners)

Answer 2

您的问题在这里：

winners = readData() # you need to return the list here...
noDuplicates(winners) # otherwise it's empty here.

这一切都可以这样做。

def main():
    winners = [x.rstrip() for x in open('WorldSeriesWinners.txt').readlines()]
    winnersND = list(set(winners))

由于您在评论中提到了这一点，因此您可以查看每个团队获胜的次数。

from collections import Counter
for winner, count in Counter(winners).iteritems():
    print '{0} has won {1} times'.format(winner, count)

Answer 3

尝试

print winners

在noDuplicates()函数中，这是一个空白列表，这就是为什么你得到一个空白列表，因为从空白列表中获取数据。

您尝试访问winners中指定的main()，但在readData()功能中更改winners，当您尝试访问该功能外的def noDuplicates(winners): winnersND = [] for x in readData(): # use readData() instead winners if x not in winnersND: winnersND.append(x) print (winnersND) winnersND = tuple(winnersND) return winnersND时，它会显示空白列表。

试试这个： -

readData()

或将data = readData()存储在变量中，以便： -

for

然后应用for x in data: . .循环

{{1}}

Python列表没有通过？

3 个答案: