如何从列表列表中的列表中提取最后一项?(Python) [英] How to extract the last item from a list in a list of lists? (Python)

问题描述

我有一个列表列表，想提取最后一个项目并将它们放在列表列表中.提取最后一个项目相对容易.但是我所有的尝试都只产生一个列表，而不是一个列表.有什么建议吗?

I have a list of lists and would like to extract the last items and place them in a lists of lists. It is relatively easy to extract the last items. But all my attempts result in one list, rather than in a list of lists. Any suggestions?

lst = [[[11, 12, 15], [12, 13, 14], [13, 14, 15], [14, 15, 17], [15, 16, 17]], [[14, 15, 18], [15, 16, 17]]]

我想从中得到的结果是: [[15，14，15，15，17，17]，[18，17]]

The result I would like from this is: [[15, 14, 15, 17, 17], [18, 17]]

例如，我尝试的是此功能:

What I tried for example, is this function:

def Extract(lst): 
    for i in lst:
        return [item[-1] for item in i]
print(Extract(lst))

但这仅给出: [15、14、15、17、17]

我也尝试过:

last = []
for i in lst:
    for d in i:
        last.append(d[-1])
last

但这给出了: [15、14、15、17、17、18、17]

有人建议如何获得 [[15，14，15，17，17，17]，[17，18]] 作为结果吗?

Any suggestions how to get [[15, 14, 15, 17, 17], [17, 18]] as the outcome?

推荐答案

我建议两次遍历列表，如下所示:

I would suggest looping through the list twice, like so:

lst = [[[11, 12, 15], [12, 13, 14], [13, 14, 15], [14, 15, 17], [15, 16, 17]], [[14, 15, 18], [15, 16, 17]]]

# Result of iteration
last_lst = []

# Iterate through lst
for item1 in lst:
    # Initialize temporary list
    last_item1 = []
    
    #Iterate through each list in lst
    for item2 in item1:
        # Add last item to temporary list
        last_item1.append(item2[-1])
        
    # Add the temporary list to last_lst
    last_lst.append(last_item1)

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