Python 从列表中获取特定字符串

Question

我在列表中有一个这样的信息列表:

example = [
    ['68', ' ?', ' 38317', ' 1st-4th', ' 2', ' Divorced', ' ?', ' Not-in-family', ' White', ' Female', ' 0', ' 0', ' 20', ' United-States', ' <=50K'],
    ['32', ' ?', ' 293936', ' 7th-8th', ' 4', ' Married-spouse-absent', ' ?', ' Not-in-family', ' White', ' Male', ' 0', ' 0', ' 40', ' ?', ' <=50K']
]

又名example[0]将是:

['68', ' ?', ' 38317', ' 1st-4th', ' 2', ' Divorced', ' ?', ' Not-in-family', ' White', ' Female', ' 0', ' 0', ' 20', ' United-States', ' <=50K']

和example[1]将是:

['32', ' ?', ' 293936', ' 7th-8th', ' 4', ' Married-spouse-absent', ' ?', ' Not-in-family', ' White', ' Male', ' 0', ' 0', ' 40', ' ?', ' <=50K']

我只想取最后一点，' <=50K' ，我该怎么做？

Answer 1

您可以使用 list comprehension 获取所有嵌套列表的最后一个元素:

[sublist[-1] for sublist in example]

这会产生 [' <=50k', ' <=50k'] .

演示:

>>> example = [
...     ['68', ' ?', ' 38317', ' 1st-4th', ' 2', ' Divorced', ' ?', ' Not-in-family', ' White', ' Female', ' 0', ' 0', ' 20', ' United-States', ' <=50K'],
...     ['32', ' ?', ' 293936', ' 7th-8th', ' 4', ' Married-spouse-absent', ' ?', ' Not-in-family', ' White', ' Male', ' 0', ' 0', ' 40', ' ?', ' <=50K'],
... ]
>>> [sublist[-1] for sublist in example]
[' <=50K', ' <=50K']

您还可以直接寻址每个嵌套列表并提取最后一个元素:

>>> example[0][-1]
' <=50K'
>>> example[1][-1]
' <=50K'