问题
I wish to know an efficient way and code saving to slice a list of thousand of elements
example:
b = ["a","b","c","d","e","f","g","h"]
index = [1,3,6,7]
I wish a result like as:
c = ["b","d","g","h"]
回答1:
The most direct way to do this with lists is to use a list comprehension:
c = [b[i] for i in index]
But, depending on exactly what your data looks like and what else you need to do with it, you could use numpy arrays - in which case:
c = b[index]
would do what you want, and would avoid the potential memory overhead for large slices - numpy arrays are stored more efficiently than lists, and slicing takes a view into the array rather than making a partial copy.
来源：https://stackoverflow.com/questions/12768504/python-an-efficient-way-to-slice-a-list-with-a-index-list