Question

我正在尝试抓取Python中列表中列表的第二项。

示例：

people = [['John Doe', u'', u'25.78', u''], ['John Doe', u'', u'13.39', u''], ['John Doe', u'', u'11.93', u'0.00'], ['John Doe', u'', u'14.97', u'0.00'], ['John Doe', u'', u'14.34', u''], ['John Doe', u'', u'21.08', u''], ['John Doe', u'', u'13.24', u''], ['John Doe', u'', u'13.11', u'0.00'], ['John Doe', u'', u'', u''], ['John Doe', u'', u'19.45', u'0.00'], ['John Doe', u'', u'17.56', u''], ['John Doe', u'', u'20.57', u''], ['John Doe', u'', u'28.50', u''], ['John Doe', u'', u'24.38', u'0.00'], ['John Doe', u'', u'31.13', u''], ['John Doe', u'', u'17.20', u''], ['John Doe', u'', u'18.52', u'0.00'], ['John Doe', u'', u'6.42', u'0.00'], ['John Doe', u'', u'17.31', u'']]

我要做的是抓住列表中每个列表的第三个元素。

我希望我的回归：

['25.78','13.39','11.93','14.97','14.34']等等。

此外，奖励积分。列表中每个项目前面的u是否会影响任何内容？

Answer 1

In [57]: people = [['John Doe', u'', u'25.78', u''], ['John Doe', u'', u'13.39', u''], ['John Doe', u'', u'11.93', u'0.00'], ['John Doe', u'', u'14.97', u'0.00'], ['John Doe', u'', u'14.34', u''], ['John Doe', u'', u'21.08', u''], ['John Doe', u'', u'13.24', u''], ['John Doe', u'', u'13.11', u'0.00'], ['John Doe', u'', u'', u''], ['John Doe', u'', u'19.45', u'0.00'], ['John Doe', u'', u'17.56', u''], ['John Doe', u'', u'20.57', u''], ['John Doe', u'', u'28.50', u''], ['John Doe', u'', u'24.38', u'0.00'], ['John Doe', u'', u'31.13', u''], ['John Doe', u'', u'17.20', u''], ['John Doe', u'', u'18.52', u'0.00'], ['John Doe', u'', u'6.42', u'0.00'], ['John Doe', u'', u'17.31', u'']]

In [58]: [p[2] for p in people]
Out[58]: 
[u'25.78',
 u'13.39',
 u'11.93',
 u'14.97',
 u'14.34',
 u'21.08',
 u'13.24',
 u'13.11',
 u'',
 u'19.45',
 u'17.56',
 u'20.57',
 u'28.50',
 u'24.38',
 u'31.13',
 u'17.20',
 u'18.52',
 u'6.42',
 u'17.31']

字符串前面的u基本上表示它们是unicode字符串。如果你想将它们转换为常规的ascii字符串（假设它们只有ascii字符）：

In [59]: [str(p[2]) for p in people]
Out[59]: 
['25.78',
 '13.39',
 '11.93',
 '14.97',
 '14.34',
 '21.08',
 '13.24',
 '13.11',
 '',
 '19.45',
 '17.56',
 '20.57',
 '28.50',
 '24.38',
 '31.13',
 '17.20',
 '18.52',
 '6.42',
 '17.31']

Answer 2

您可以使用简单的列表推导来获取第三个元素。

numbers = [i[2] for i in people]

u表示它是一个unicode字符串。假设它包含ascii个字符（在这种情况下它包含），如果你不想要unicode，你可以使用str。

numbers = [str(i[2]) for i in people]

Answer 3

result = [each[2] for each in people]
print(result)

Answer 4

在这里它是numpy

people = numpy.array(people)
print people[:,2]

Answer 5

另外，只是为了好玩：

result = []
for x in range(len(people)):
    result.append(people[x][2])

在Python列表中获取第二个元组

5 个答案: