Python

Question

我有例如索引值：

x = [1, 4, 5, 7]

我有一个元素列表：

y = ['this','is','a','very','short','sentence','for','testing']

我想要 return 值

['is','short','sentence','testing']

当我尝试打印时说：

y[1]

它会很乐意 return ['is']。但是，当我执行 print(y[x])) 时，它只会 return 什么都没有。我如何打印所有这些索引？奖励：然后加入他们。

Answer 1

这应该可以完成工作：

' '.join([y[i] for i in x])

Answer 2

试试这个列表组合 [y[i] for i in x]

>>> y = ['this','is','a','very','short','sentence','for','testing']
>>> x = [1, 4, 5, 7]
>>> [y[i] for i in x]                    # List comprehension to get strings
['is', 'short', 'sentence', 'testing']
>>> ' '.join([y[i] for i in x])          # Join on that for your bonus
'is short sentence testing'

其他方式

>>> list(map(lambda i:y[i], x) )         # Using map
['is', 'short', 'sentence', 'testing']

Answer 3

您将需要一个 for 循环来遍历您的索引列表，然后用索引轴化您的列表。

for i in x: #x is your list, i will take the 'value' of the numbers in your list and will be your indexed
    print y[i]

    > is
      short
      sentence
      testing

Answer 4

如果你有numpy包，你可以这样做

>>> import numpy as np
>>> y = np.array(['this','is','a','very','short','sentence','for','testing'])
>>> x = np.array([1,4,5,7])
>>> print y[x]
['is' 'short' 'sentence' 'testing']

Python - 如何打印给定多个索引的列表的值？

Python - how to print values of a list given many indexes?

printing

list

indices